Help:CS1 errors

Prior tae 2013, the CS1|2 templates uised the meta-template {{citation/core}}. In 2013, as pairt o the WP:LUA project, Wikipedia editors upgraded the CS1|2 series of templates tae uise a single Lua module. Module:Citation/CS1 is the ingine that controls how CS1|2 citations are displayed and how citation data are passed tae external referencing tuils throu COinS metadata. The benefits o the upgrade are enhanced performance, reduced complexity and redundancy, an for the purposes of this page, improved error detection, categorization, an reporting.

Category:CS1 errors is the general errors category and Category:CS1 maintenance is the general maintenance category.

Controlling error message display

While maist o the Citation Style 1 and Citation Style 2 error messages are visible tae aw readers, some remain hidden. Editors who wish tae see aw o the CS1|2 error messages can dae sae bi updating thair common or skin CSS stylesheet tae include:

.citation-comment {display: inline !important;} /* show all Citation Style 1 error messages */

Even with this css installed, aulder pages in Wikipedia's cache mey nae hae been updated tae shaw thir error messages even tho the page is listed in ane o the tracking categories. A WP:NULLEDIT will resolve that issue.

The abuin code is required if you wish tae see maintenance category messages:

Category:CS1 maintenance (link)

Editors who dae nae wish tae see ony o the CS1 error messages can hide them aw bi updating thair common or skin CSS stylesheet tae include:

.citation-comment {display: none;} /* hide all Citation Style 1 error messages */

|access-date= requires |url=

Help desk

(error message hidden bi default)

The |access-date= (or its alias, |accessdate=) is the date that the online resoorce addressed bi |url= wis added tae the article. If |access-date= haes been included in the citation wioot |url= then this message appears. If the citation daes nae uise a web link, then |access-date= is redundant and should be removed.

When the online resoorce haes a publication or ither fixed date associated with it, |access-date= is of leemitit value tho mey be useful in identifyin an appropriate archived version o the resoorce. Wioot |url=, |access-date= is nae considered useful.

Tae resolve this error, provide a value for |url= or remove |access-date=. Editors should try tae determine why the citation haes |access-date= wioot |url=. For example, the citation mey never hae haed a |url=, or |url= mey hae been removed acause it links tae a site that violates the creautor's copyright (see WP:COPYLINK), or acause |url= wis deemed tae be dead and (mistakenly) removed. If the citation never haed |url= or it wis removed for copyright violations, remove |access-date=. When a dead |url= haes been removed, restore the |url= and if possible repair it (see WP:LINKROT).

Pages with this error are automatically placed in Category:Pages using citations with accessdate and no URL.

|archive-url= is malformed

Help desk

Archive.org allows a variety of urls tae access snapshots of an archived page. Some of thir are:

https://web.archive.org/web/YYYYMMDDhhmmss/http://www.example.com – a single snapshot; this is the preferred form for use with |archive-url=

https://web.archive.org/web/*/http://www.example.com – a wildcard search results page; useful for locating an appropriate snapshot but not appropriate in a citation

https://web.archive.org/web/201603/http://www.example.com – incomplete timestamp; archive.org returns the most recent snapshot

https://web.archive.org/save/http://www.example.com – saves a new snapshot of the current target; do not use this form

Thare are twa forms o the basic url:

https://web.archive.org/<timestamp>/... – the old form

https://web.archive.org/web/<timestamp><flags>/... – the new form

The error message identifies the reason for the message. The reasons are:

– the archive.org url is the save command

– web/ was expected but something else was found

– the timestamp portion of the url path is not 14 digits

– the flag portion of the url path (if present; new form urls only) is not 2 lowercase letters followed by an underscore: 'id_'

– liveweb.archive.org is a deprecated form of the domain name

When the archive.org url haes ony of thir errors, Module:Citation/CS1 daes nae link tae archive.org and emits an appropriate error message.

Tae resolve this error, choose the url of an appropriate snapshot frae those held at archive.org. Search for the target url.

Pages with this error are automatically placed in Category:Pages with archiveurl citation errors.

|archive-url= requires |archive-date=

Help desk

|archive-date= (or its alias, |archivedate=), identifies the date that the web resoorce wis archived.

Tae resolve this error, provide a value for |archive-date=. For web resoorces archived at archive.org, the archival date can be foond in the |archive-url=; for resoorces archived at webcitation.org, the cache date is included in the archive header.

Pages with this error are automatically placed in Category:Pages with archiveurl citation errors.

|archive-url= requires |url=

Help desk

A properly formatted citation that includes |archive-url= and |archive-date= requires |url=. When the citation includes |dead-url=no, the ordering of elements in the rendered citation is changed tae put the oreeginal url first.

Tae resolve this error, provide a value for |url=. For web resoorces archived at archive.org, the oreeginal url can be foond in the |archive-url= value; for resoorces archived at webcitation.org, the oreeginal url is included in the archive header.

Pages with this error are automatically placed in Category:Pages with archiveurl citation errors.

|arxiv= required

Help desk

{{cite arxiv}} requires ane, but nae baith, o the identifier parameters |arxiv= or |eprint=.

Tae resolve this error, ensure that the template haes |arxiv= or |eprint= with a properly biggit value.

Pages with this error are automatically placed in Category:CS1 errors: arXiv.

|chapter= ignored

Help desk

Citation Style 1 templates {{cite web}}, {{cite news}}, {{cite journal}}, {{cite press release}}, {{cite podcast}}, {{cite newsgroup}}, as well as template {{citation}} whan it uses |work= or ony of its aliases, dae nae support |chapter= or the aliases |contribution=, |entry=, |article=, or |section=.

Tae resolve this error, uise a mair appropriate citation template, or place the content o the |chapter= parameter in |title=.

Pages with this error are automatically placed in Category:CS1 errors: chapter ignored.

Check |arxiv= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |arxiv=, a test is done tae see if the arXiv identifier conforms with the arXiv identifier scheme. The identifier is checked for a valid nummer of deegits in the article id; valid year and month values; and properly-placed hyphens, slashes, an dots.

Tae resolve this error, ensure that the |arxiv= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: arXiv.

Check |asin= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |asin=, a test is done tae see if the ASIN identifier is contains ten upper-case alphanumeric characters wioot punctuation or spaces and that if the first character is numeric, that the ASIN conforms tae the rules for a ten-digit ISBN.

Tae resolve this error, ensure that the |asin= value is correct.

If the |asin= value is correct and aw-numeric, uise |isbn= instead and delete ony |asin-tld= parameters. Articles with CS1 citations that uise |asin= with aw numeric values are categorized in Category:CS1 maint: ASIN uses ISBN.

Pages with this error are automatically placed in Category:CS1 errors: ASIN.

Check |bibcode= <message>

Help desk

When Citation Style 1 and Citation Style 2 templates contain |bibcode=, a test is done tae see if the bibcode identifier haes the proper format. Bibcodes are expected tae match thir requirements:

length must be 19 characters (<message> = '')

characters in position(s): (except as specified otherwise, violations produce '' in the <message> portion of the error message):

1–4 must be digits and must represent a year in the range of 1000 – next year (<message> = '')

5 must be a letter

6–8 must be letter, ampersand, or dot (ampersand cannot directly precede a dot; &. (<message> = ''))

9 must be letter or dot

10–18 must be letter, digit, or dot

19 must be a letter or dot

Tae resolve this error, ensure that the |bibcode= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: bibcode.

Check |biorxiv= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |biorxiv=, a test is done tae see if the bioRxiv identifier comprises sax numeric characters wioot punctuation or spaces. A common error is tae include the bioRxiv url (http://dx.doi.org/10.1101/<BIORXIV>), or the biorxiv doi (10.1101/<BIORXIV>)

Tae resolve this error, ensure that the |biorxiv= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: bioRxiv.

Check |citeseerx= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |citeseerx=, a test is done tae see if the CiteSeerX identifier haes the proper format. The expected identifier is the value assigned tae the ?doi= query key in the URL o a CiteSeerX document. (This query key should nae be confused with a Digital Object Identifier: it should nae be input as |doi=.)

For instance, if you want tae link tae http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.220.7880, uise |citeseerx=10.1.1.220.7880.

Pages with this error are automatically placed in Category:CS1 errors: citeseerx.

Check date values in: |<param1>=, |<param2>=, ...

Help desk

When Citation Style 1 and Citation Style 2 templates contain date-holding parameters, an automated test is done tae see if the dates are real dates that comply with a subset o the date rules in Wikipedia's Manual of Style, specifically checking for violations of MOS:DATEFORMAT.

Tae resolve this error, ensure that the date is an actual date and that the date format follows the in the named parameter. See examples of unacceptable dates and how tae fix them, ablo. Or, some conceptual issues tae leuk for:

• impossible dates (e.g., 29 Februar 2011)
• |access-date= must specify a day, nae juist a month or year.
• misplaced, incorrect, or extraneous punctuation
• extraneous text
• hyphens or slashes instead of en dashes in date ranges (en dashes are required)
• misspelling or improper capitalization (see for mair detail that is nae in )
• ither unacceptable date formats listed in
• mair nor ane date in a date-holding parameter
• Does nae handle years afore 100 AD, includin BCE/BC dates. Try using parameter |orig-year= instead.

See Help: Citation Style 1 for information aboot limitations in the CS1 citation templates' handling of date formats. The MOS section on date ranges describes how tae separate dates in a date range. Do nae uise  , –, or {{spaced ndash}} as thir corrupt the metadata. Tae add an en dash, uise the CharInsert edit tuil or see Wikipedia:How to make dashes. A bot is eften able tae correct the separator, providit the oweraw format is unambiguous.

Future dates in |date= in CS1|2 citations are leemitit tae current year + 1; that is, for 2024, citation dates in 2025 are acceptable but citation dates in 2026 and beyond are nae.

Dates prior tae 1582 are treatit as Julian calendar dates. Dates frae 1582 onward are treatit as Gregorian calendar dates. The Julian calendar wis uised in some places until approximately 1923. Three Julian calendar dates in the owerlap period, 29 Februar in the years 1700, 1800, an 1900, will cause this error message acause those years are nae leap years in the Gregorian calendar.

The access date (in |access-date=) is checked tae ensure that it contains a full date (day, month, an year) and is atween 15 Januar 2001 (the founding date of Wikipedia) an the day's date plus ane day, acause it represents the date that an editor viewed a web-based soorce tae verify a statement on Wikipedia. Because editors mey be in time zones that are ane day ahead o the UTC date, ane extra day is acceptit.

Pages with this error are automatically placed in Category:CS1 errors: dates.

Examples of unacceptable dates and how tae fix them

Issue	Unacceptable	Acceptable
Hyphen in date range (uise en dash)	|date=2002-2003	|date=2002–2003
Sleesh in date range (uise en dash)	|date=2002/2003 or |date=July/August, 2003	|date=2002–2003 or |date=July–August, 2003
Hyphen in date range (uise en dash)	|date=April-May 2004	|date=April–May 2004
Missing space aroond en dash for range of full dates	|date=April 2003–May 2004	|date=April 2003 – May 2004
Month capitalization	|date=28 february 1900	|date=28 February 1900
Month capitalization	|date=28 FEBRUARY 1900	|date=28 February 1900
Saison capitalization	|date=spring 2011	|date=Spring 2011
Future date (typo)	|date=2102	|date=2012
Access date in future (see note abuin)	|accessdate=December 25, 2024	|accessdate=December 23, 2024
Access date impossibly far in the past (typo)	|access-date=1 January 2001	|access-date=1 January 2010
Access date anly specifies month	|access-date=January 2015	|access-date=12 January 2015
Ambiguous date range or year and month	|date=2002-03	|date=2002–2003 |date=March 2002
Bad abbreviation	|date=Febr. 28, 1900	|date=Feb 28, 1900 |date=February 28, 1900
Nonexistent date	|date=February 29, 1900
Comma in month and year	|date=February, 1900	|date=February 1900
Comma in saison	|date=Winter, 1900–1901	|date=Winter 1900–1901
Missing comma in format which requires it	|date=February 28 1900	|date=February 28, 1900 or |date=28 February 1900
Non-date text	|date=2008, originally 2000	|date=2008 |orig-year=2000
Zero-padding	|date=January 04, 1987	|date=January 4, 1987
Date with slashes	|date=12/6/87	|date=December 6, 1987 |date=12 June 1987
Twa-digit year	|date=87-12-06	|date=1987-12-06
Ane-digit month or day	|date=2007-3-6	|date=2007-03-06
Wikified date	|date=[[April 1]], [[1999]]	|date=April 1, 1999
"mm-dd-yyyy" or "dd-mm-yyyy" date format	|date=07-12-2009	|date=7 December 2009 or |date=12 July 2009 or |date=July 12, 2009 or |date=December 7, 2009
Approximate or uncertain dates	|date=circa 1970 or |date={{circa}} 1970	|date=c. 1970

Check |doi= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |doi=, a test is done tae see if the prefix portion o the DOI value contains the proper 10. registry identifier. Additionally, the |doi= value is checked tae mak sure that it daes nae contain spaces or en dashes and daes nae end with punctuation. Further validation o the DOI is nae performed.

Tae resolve this error, ensure that the |doi= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: DOI.

Check |hdl= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |hdl=, a test is done tae see if the hdl value looks lik a properly defined value. The |hdl= value is checked tae mak sure that it daes nae contain spaces or en dashes and daes nae end with punctuation. Further validation o the hdl is nae performed.

Tae resolve this error, ensure that the |hdl= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: HDL.

Check |isbn= value

Help desk

Citation Style 1 and Citation Style 2 templates that contain |isbn= are checked tae ensure that the ISBN is the proper lenth (ten or thirteen deegits), that the ISBN uses the correct optional separators (semple space or hyphen), and that the final check digit is correct accordin tae the ISBN specification. Anly ane ISBN is allowed in this field acause the whole |isbn= value is included in the citation's COinS metadata. See an aa Wikipedia:COinS. Mair than ane ISBN, or characters that are nae pairt o the ISBN, corrupt the COinS metadata and mey an aa corrupt the link tae Special:BookSources.

The error message <type> indicator can be:

– ISBN is not 10 or 13 digits

– ISBN has one or more incorrect digits; look for typos and transposition

– ISBN has one or more 'digits' that is not in the allowed set appropriate to ISBN length

– 13-digit ISBNs must begin with '978' or '979'

– 10-digit ISBNs with the mis-positioned 'X' character

Tae resolve this error, ensure that the |isbn= value is correct, that anly ane ISBN is uised, that the proper optional separators are uised, an that no ither text is included. Uise the 13-digit ISBN when it is available. When a 10-digit ISBN is uised, if the check digit is a lowercase 'x', chynge it tae an uppercase 'X'.

• Do nae try tae resolve the error bi simply recalculating the check digit. The check digit is thare tae check whether the main pairt o the nummer is correct. If the ISBN is failing tae validate, it is likely that thare is a typo in the main pairt o the nummer. In this case, recalculating the check digit results in an apparently valid ISBN that leads tae the wrong soorce (or tae nowhere).
• If you anly hae a 10-digit ISBN, dae uise the nummer as-is, dae nae try tae convert it tae the 13-digit form.
• If the ISBN as printed in your soorce is refusing tae validate, dae check baith the front matter an the beuk cover for ISBNs. It is nae uncommon for the ISBN tae be misprinted in the front matter but correct on the cover.
• Do preview your edit and check that the new ISBN daes nou link tae the correct soorce.

In very rare cases, publishers hae released beuks with malformed ISBNs. If you are certain that a non-conforming ISBN truly corresponds tae the published wirk, then you can add |ignore-isbn-error=true tae the citation in order tae suppress the error message. In mony cases, beuks mey hae been reissued with a corrected ISBN. Uise a corrected ISBN whan possible.

Whiles thare are nummers assigned tae |isbn= that appear tae be legitimate – lenth is right, check digit is correct – but that arena true ISBN nummers. This tool mey be helpful.

See an aa Wikipedia:ISBN.

Pages with this error are automatically placed in Category:CS1 errors: ISBN.

Check |ismn= value

Help desk

Citation Style 1 and Citation Style 2 templates that contain |ismn= are checked tae ensure that the ISMN is the proper lenth (thirteen deegits), that the ISMN uses the correct optional separators (semple space or hyphen), and that the final check digit is correct accordin tae the ISMN specification. Anly ane ISMN is allowed in this field acause the whole |ismn= value is included in the citation's COinS metadata. See an aa Wikipedia:COinS. Mair than ane ISMN, or characters that are nae pairt o the ISMN, corrupt the COinS metadata.

Tae resolve this error, ensure that the |ismn= value is correct, that anly ane ISMN is uised, that the proper optional separators are uised, an that no ither text is included. Make sure that the ISMN contains exactly 13 deegits.

Pages with this error are automatically placed in Category:CS1 errors: ISMN.

Check |issn= value

Help desk

Citation Style 1 and Citation Style 2 templates that contain |issn= and/or |eissn= are checked tae ensure that the ISSN is the proper lenth (aicht deegits) and that the final check digit validates accordin tae the ISSN specification. Anly ane each of ISSN and eISSN is allowed in this field acause the whole |issn= and |eissn= values are included in the citation's COinS metadata. See an aa Wikipedia:COinS. The ISSN and eISSN are always rendered as twa fower-digit nummers separated with a hyphen.

Tae resolve this error, ensure that the |issn= and |eissn= values are correct, that anly ane value per parameter is uised, an that no ither text is included (allowable characters are 0-9, X, an -). If the check-digit is a lowercase 'x', chynge it tae an uppercase 'X'.

Pages with this error are automatically placed in Category:CS1 errors: ISSN.

Check |jfm= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |jfm=, a test is done tae see if the jfm identifier value looks lik a properly defined value. The |jfm= identifier is checked tae mak sure that it haes the form: nn.nnnn.nn whaur n is ony digit 0–9. Further validation o the jfm identifier is nae performed.

Tae resolve this error, ensure that the |jfm= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: JFM.

Check |lccn= value

Help desk

The |lccn= parameter is the Library of Congress Control Number identifier. It is checked tae ensure that the identifier is the proper lenth and haes the correct initial deegits.

LCCN is a character string 8–12 characters lang. The lenth o the LCCN dictates the character teep o the initial 1–3 characters; the rightmost aicht are always deegits.

LCCN format description

Lenth	Description
8	aw characters are deegits
9	first character is a lawer case letter
10	first twa characters are either baith lawer case letters or baith deegits
11	first character is a lawer case letter, second and third characters are either baith lawer case letters or baith deegits
12	first twa characters are baith lawer case letters

Further validation is nae performed.

Tae resolve this error, ensure that the |lccn= value is correct and that thare are no ither letters, punctuation, or ither characters.

Pages with this error are automatically placed in Category:CS1 errors: LCCN.

Check |message-id= value

Help desk

The |message-id= parameter holds the unique identifier associated with a netnews message. The value in |message-id= is checked tae mak sure that it contains @ atween left and right identifiers. |message-id= is an aa checked tae mak sure that the first character is nae < an the last character is nae >. Module:Citation/CS1 adds the uri news: tae the value in |message-id=. If the value in |message-id= is wrapped in <...> characters, the link creautit fails.

Further validation is nae performed.

Tae resolve this error, ensure that the |message-id= value is correct, that it contains @ and is nae wrapped in <...> characters.

Pages with this error are automatically placed in Category:CS1 errors: message-id.

Check |mr= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |mr=, a test is done tae see if the mr identifier value looks lik a properly defined value. The |mr= identifier is checked tae mak sure that it contains anly deegits and that it is no mair nor seiven deegits in lenth. Further validation o the mr identifier is nae performed.

Tae resolve this error, ensure that the |mr= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: MR.

Check |oclc= value

Help desk

The |oclc= parameter is the OCLC identifier. Anly a single OCLC identifier is allowed. The identifier must be in ane of thir forms:

1. prefix ocm followed bi 8 deegits
2. prefix ocn followed bi 9 deegits
3. prefix on followed bi 10 deegits
4. prefix (OCoLC) followed bi a variable nummer of deegits wioot leadin zeros
5. 1 tae 10 deegits wioot prefix

Further validation is nae performed.

Tae resolve this error, ensure that the |oclc= value is correct.

A tip for fixing this error: Editors whiles place valid ISBN, LCCN, ASIN, or ither identifiers in |oclc=.

Pages with this error are automatically placed in Category:CS1 errors: OCLC.

Check |ol= value

Help desk

The |ol= parameter is the Open Library identifier. The identifier is ane or mair deegits followed bi a last character that is either A (authors), M (beuks), or W (wirks). Further validation is nae performed.

Tae resolve this error, ensure that the |ol= value is correct. Do nae include "OL" in the value.

Pages with this error are automatically placed in Category:CS1 errors: OL.

Check |<param>-link= value

Help desk

Thir link-holding parameters and thair matching title-holding parameters are combined tae creaut a wirkin wikilink tae a relatit article.

|author-link=

|contributor-link=

|editor-link=

|episode-link=

|series-link=

|subject-link=

|title-link=

|translator-link=

|author=

|contributor=

|editor=

|episode=

|series=

|subject=

|title=

|translator=

(Parameters checked for this error mey an aa be o the form |authorlink=, |authorlink1=, |author1-link=, or |author-link1=.)

This error occurs whan ony of thir |<param>-link= parameters contain a wikilink or a URL, or thay contain ony o the characters nae permitted in Wikipedia article titles per WP:TITLESPECIALCHARACTERS (except _ (underscore), uised as a replacement for spaces, an #, uised as a fragment identifier whan linking tae article sections). The prohibited characters are: < > [ ] | { }.

The |<param>-link= parameter value should contain anly the title o a Wikipedia article or a link tae a section o a Wikipedia article. Module:Citation/CS1 checks the |<param>-link= parameter values for wikimarkup and for a URI scheme (http://, https://, the protocol relative scheme //, etc.).

This error can an aa be caused whan thare is a |<param>-link= value an the matching |<param>= parameter contains a wikilink.

Tae resolve this error, dae ane o the follaein:

• Ensure that the |<param>-link= value is the full name o a Wikipedia article (wioot brackets) or a section of an article, an nae a link tae an external web site.
• Make sure that thare are no wikilinks in the matching |<param>= parameters.
• If you want tae link tae a URL ootside of Wikipedia, muive the link tae |url= or a seemilar parameter, if ane is available in the template you are using.

Pages with this error are automatically placed in Category:CS1 errors: parameter link.

Check |pmc= value

Help desk

The |pmc= parameter is the PubMed Central identifier. PMCs are sequential nummers beginnin at 1 and counting up. Module:Citation/CS1 checks the PMC identifier tae mak sure that the value is a nummer greater than zero and less nor 5000000 and that the identifier contains anly deegits. Further validation is nae performed.

Tae resolve this error, ensure that the |pmc= value is correct, an that thare are no letters, punctuation, or ither characters. Do nae include "PMC" in the value.

Pages with this error are automatically placed in Category:CS1 errors: PMC.

Check |pmid= value

Help desk

The |pmid= parameter is the PubMed identifier. PMIDs are checked tae ensure that the identifier is a semple nummer wioot punctuation or spaces with a value greater than or equal tae 1 and less nor or equal tae 30000000. Further validation is nae performed.

Tae resolve this error, ensure that the |pmid= value is correct. If you find something that looks lik a PMID and begins with "PMC", uise |pmc= instead of |pmid=.

Pages with this error are automatically placed in Category:CS1 errors: PMID.

Check |ssrn= value

Help desk

The |ssrn= parameter is the Social Science Research Network identifier. SSRNs are checked tae ensure that the identifier is a semple nummer wioot punctuation or spaces with a value greater than or equal tae 100 and less nor or equal tae 3500000. Further validation is nae performed.

Tae resolve this error, ensure that the |ssrn= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: SSRN.

Check |url= value

Help desk

External links in Citation Style 1 and Citation Style 2 templates are made frae twa pairts: the title (|title=, |chapter=, etc.) an the URL (|url=, |archive-url=, |chapter-url=, |lay-summary=, etc.). The |url= parameter and ither URL parameters must begin with a supported URI scheme. The URI schemes http://, https:// an the protocol relative scheme // are maist commonly uised; irc://, ircs://, ftp://, news:, mailto: and gopher:// are an aa supported.

The URL field is checked tae ensure that it contains anly Latin characters and daes nae contain spaces. The URL mey be protocol relative (begins with //). If thare are no spaces an the URL is nae protocol relative, then the scheme must comply with RFC 3986.

Top- and second-level domain names are checked for proper form. Generally, tap-level domain names must be twa or mair letters; second-level domain names must be twa or mair letters, deegits, or hyphens (first and last character must be a letter or digit). Single-letter second-level domains are supported for:

all ccTLDs (the country code is not validated)

the .org TLD

certain letters of the .com TLD (q, x, z)

certain letters of the .net TLD (i, q)

Third- and subsequent-level domain names are nae checked. The path portion o the URL is nae checked.

Tae resolve this error, ensure that |url= and ither URL parameters contain valid URLs. Online tuils are available tae internationalize URLs that are written in non-Latin scripts:

"IDN Conversion Tool". Verisign.

"IDNA Conversion tool". IDNA-converter.com.

Pages with this error are automatically placed in Category:Pages with URL errors.

Check |zbl= value

Help desk

When Citation Style 1 and Citation Style 2 templates contain |zbl=, a test is done tae see if the zbl identifier value looks lik a properly defined value. The |zbl= identifier is checked tae mak sure that it haes the form: nnnn.nnnnn whaur n is ony digit 0–9. Up tae three leadin zeros in the first quartet mey be omeetit. Further validation o the zbl identifier is nae performed.

Tae resolve this error, ensure that the |zbl= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: ZBL.

Cite uses deprecated parameter |<param>

Help desk

Ower time, some parameters hae acome obsolete or unnecessary. When this happens, the parameters are identified as deprecated. Editors are encouraged tae uise ither parameters that accomplish the same purpose as those that hae been deprecated. The CS1|2 deprecated parameters are listed in the follaein table, alang with recommended replacement parameters. Parameter names are case-sensitive. Editors should expect that support for deprecated parameters will be withdrawn.

Deprecated CS1|2 parameters

Deprecated parameter	Replace with
|doi_brokendate=	|doi-broken-date=
|doi_inactivedate=	|doi-inactive-date=
|template doc demo=	|template-doc-demo=
|trans_chapter=	|trans-chapter=
|trans_title=	|trans-title=

Tae resolve this error, uise a supported parameter.

Pages with this error are automatically placed in Category:CS1 errors: deprecated parameters.

|contributor= ignored

Help desk

Anly uised in beuk citations, |contributor= identifies the author o a contreibution, teepically an afterword, forward, introduction, preface, etc., tae anither (primary) author's wirk. This error occurs whan |contributor= is uised in a template that is nae {{cite book}} or {{citation}} or is ane of thir twa templates and ane o the |work= parameter aliases is set.

Tae resolve this error, choose a mair appropriate CS1 or CS2 template or remove |contributor=.

Pages with this error are automatically placed in Category:CS1 errors: contributor.

|contributor= requires |<param>=

Help desk

Anly uised in beuk citations, |contributor= identifies the author o a contreibution, teepically an afterword, forward, introduction, preface, etc., tae anither (primary) author's wirk. As sic, the primary author is required (|author= or appropriate alias) as is the title o the contreibution (|contribution=).

Tae resolve this error, include the beuk's primary author in |author1=, or |last1=, |first1=, or |vauthors= and include the contreibution title in |contribution=; or remove |contributor=.

Pages with this error are automatically placed in Category:CS1 errors: contributor.

Empty citation

Help desk

A Citation Style 1 or Citation Style 2 template merked as "Empty" contains no recognizable parameter identifiers. For example, this citation is merked as "empty" even tho it contains usable information:

{{cite web | http://www.foobar.com | The Foobar Bar}}

The citation is "empty" acause it daes nae contain the necessary parameter identifiers (in this case |url= and |title=) that tell {{cite web}} how tae uise the information that the citation daes contain.

A citation is an aa merked as "empty" whan it contains anly parameters that it doesn't recognise:

{{cite book |titolo=The Foobar Bar |anno=2015}}

This citation is empty acause the Italian-language parameters |titolo= and |anno= are nae recognised as valid parameter names on the Inglis Wikipedia.

"Empty citation" mey an aa mean that an editor meant tae uise anither template entirely. Perhaps the editor uised {{citation}} whan the intent wis tae uise {{citation needed}} or {{quote}}.

Tae resolve this error, add appropriate parameter identifiers, translate foreign language parameter names tae thair Inglis equivalents, or replace the CS1|2 template with a mair appropriate template.

Pages with this error are automatically placed in Category:Pages with empty citations.

External link in |<param>=

Help desk

This error occurs whan ony o the CS1 or CS2 citation title-holding parameters – |title=, |chapter=, |publisher=, |work= or ony of its aliases: |journal=, |magazine=, |newspaper=, |periodical= and |website= – haud an external link (URL). External links in thir parameters corrupt the citation's metadata and can be the soorce o a variety of ither error messages.

Tae resolve this error, remove the external link frae the identified parameter. Consider placin the external link in a mair appropriate parameter:

• for |chapter=, the URL mey belong in |chapter-url=.
• for ither parameters, it mey belong in |url=.

Pages with this error are automatically placed in Category:CS1 errors: external links.

|firstn= missing |lastn= in Authors/Editors list

Help desk

Citation Style 1 and Citation Style 2 templates requires a |lastn= parameter for each |firstn= parameter in a citation. Author and editor lists are checked for proper last/first pairing. CS1|2 will emit this error message for the first mismatch it detects. If thare are mair last/first mismatches in a citation, subsequent mismatches are nae detected.

Thare is no requirement that each |lastn= hae a matching |firstn=.

The error message uses a sort of shorthand: |lastn= can refer tae ony o the legitimate |author= aliases in the authors leet. Similarly, |lastn= refers tae ony o the |editor-last= aliases in the editors leet.

Tae resolve this error, ensure that each |firstn= haes a corresponding |lastn=.

Pages with this error are automatically placed in Category:CS1 errors: missing author or editor.

|format= requires |url=

Help desk

• (error message hidden bi default)
• (error message hidden bi default)

Thir errors occur whan Citation Style 1 and Citation Style 2 templates uise |format= or |...-format= wioot an aa providin a corresponding URL for |url= or |...-url=, respectively. The |format= and |...-format= parameters are uised tae specify the file format o a web resoorce (e.g. PDF, DOC, XLS, etc.). In some cases an editor mey hae intendit tae uise |type= tae specify a kynd of document (e.g. haurd cover, paperback, pamphlet, etc.) The |format= and |...-format= value is always displayed.

The leet of |...-format= parameters is:

|archive-format=, |chapter-format=, |conference-format=, |contribution-format=, |event-format=, |lay-format=, |section-format=, |transcript-format=

As of 29 November 2014, |chapter-format= is a new parameter. Citations that relied on the auld, somewhat odd uise of |url= and |format= mey need adjustment.

Tae resolve this error, remove |format= or |chapter-format=; define |url= or |chapter-url=; or chynge |format= tae |type= (or tae |chapter-format= if |chapter-url= is uised wioot |url=.

Pages with this error are automatically placed in Category:Pages using citations with format and no URL.

Invalid <param>=<value>

Help desk

Tae function properly, some parameters are leemitit tae a certain set of acceptable values. This error message indicates that a parameter haes been assigned a value that is nae a member o the parameter's defined set of acceptable values.

Parameters with leemitit acceptable values

parameter	acceptable values
|dead-url=	no, true, y, yes, unfit, usurped
|df=	dmy, dmy-all, mdy, mdy-all, ymd, ymd-all
|ignore-isbn-error=	true, y, yes
|last-author-amp=
|mode=	cs1, cs2
|name-list-format=	vanc
|nopp=	true, y, yes
|no-tracking=
|registration=
|subscription=
|url-access=	subscription, registration, limited
|bibcode-access=	free
|doi-access=
|hdl-access=
|jstor-access=
|ol-access=
|osti-access=

Tae resolve this error, uise an appropriate value.

Pages with this error are automatically placed in Category:CS1 errors: invalid parameter value.

Missing |lastn= in Authors/Editors list

Help desk

Sae that aw authors and editors are listed in a rendered citation, Citation Style 1 and Citation Style 2 templates requires n in |lastn= (and its aliases) tae increment bi 1 for each author or editor. This error message is emitted whan thare is a 'hole' in the numbering (an author leet made up of |author1= and |author3= but wioot |author2= for example).

The test will nae detect a 'hole' that is lairger than 1. It is presumed that whan |authorn= and |authorn+1= are baith nae present, then the test haes reached the end o the leet.

The error message uses a sort of shorthand: |lastn= can refer tae ony o the legitimate |author= aliases in the authors leet. Similarly, |lastn= refers tae ony o the |editor-last= aliases in the editors leet.

Tae resolve this error, ensure that the numbering o the |lastn= parameters increments properly.

Pages with this error are automatically placed in Category:CS1 errors: missing author or editor.

Missing or empty |title=

Thare are twa slichtly different error conditions that can arise whan CS1 citations lack appropriate titles. In each case, CS1 reports this error message. The necessary resolution mey vary dependin on the cause o the error. The error message links tae the appropriate description ablo.

Bare URL without a title

Help desk

Aw Citation Style 1 and Citation Style 2 templates report this error whan ane o the URL-containing parameters canna be paired with an associated title. This error mey an aa occur whan |title= canna be linked with |url= acause the citation an aa contains a conflicting |title-link= parameter.

URL-containing parameters and associated title parameters

URL parameters	Title parameters
|archive-url=	|title=
|chapter-url=	|chapter=, |contribution=, |entry=, |article=
|conference-url=	|conference=
|contribution-url=	|chapter=, |contribution=, |entry=, |article=
|transcript-url=	|transcript=
|url=	|title=

A unique case exists: if |pmc= haes a value and |url= is omeetit or empty, then |title= is linked with the same URL as the PMC.

Because URLs are ugly and generally uninformative, it is expected that editors should provide a meaningful title for each URL. In maist cases this can be accomplished bi using the |title= parameter.

Tae resolve this error, provide an appropriate title for the URL-containing parameter. In the case whaur |url= and |title-link= are contending for |title= you must choose which ane tae keep. Consider muivin |url= or |title-link= tae a mair suitable parameter.

Pages with this error are automatically placed in Category:Pages with citations having bare URLs.

Citation without a title of any form

Help desk

This error occurs for Citation Style 1 and Citation Style 2 templates whan aw of |title=, |trans-title=, and |script-title= are omeetit or left blank. At least ane of thir title parameters must be providit for each citation.

{{cite episode}} will shaw this error if |series= is omeetit or left blank (even if a |title= is providit).

Whiles this error occurs acause an editor haes uised a CS1|2 citation as a shortened footnote whan {{sfn}} or ane o the {{harv}} faimily of templates wad hae been mair appropriate. This error an aa occurs whan an editor uised {{citation}} but intendit tae uise {{citation needed}}.

Tae resolve this error, provide a value for |title=, |trans-title=, and/or |script-title= or replace the CS1|2 template with a mair appropriate template. If you are listing a periodical or an issue o a periodical in a bibliography rather than within <ref>...</ref> tags, {{List journal}} mey be mair appropriate.

Pages with this error are automatically placed in Category:Pages with citations lacking titles.

Missing or empty |url=

Help desk

(error message hidden bi default)

This error message is reportit bi {{cite web}}, {{cite podcast}}, and {{cite mailing list}} whan the template parameters |url= and |archive-url= are baith missing, blank or nae properly entered. Note that |website= or |work= is the name o the site, nae the URL.

Tae resolve this error, provide a value for |url= or uise a mair appropriate template sic as {{cite book}}, {{cite journal}} or ither Citation Style 1 or Citation Style 2 template.

Pages with this error are automatically placed in Category:Pages using web citations with no URL.

More than one of |<param1>=, |<param2>=, and |<param3>= specified

Help desk

This error occurs whan a Citation Style 1 or Citation Style 2 template includes mair nor ane parameter that maps tae the same meanin. For example, |author=, |last=, and |last1= are aw synonyms of each ither, sae no mair nor ane of thir parameters should ever be uised in a single template.

Tae resolve this error, remove or modify the redundant parameter(s).

This error occurs whan a CS1 or CS2 template uses mair nor ane teep of author or editor name-leet style. Thare are three kinds of incompatible author-name-leet styles:

|authorn= and |lastn= / |firstn= (and their various aliases), |vauthors=, and |authors=

and similarly, three editor-name-leet styles:

|editorn= and |editor-lastn= / |editor-firstn= (and their various aliases), |veditors=, and |editors=

Tae resolve this error, choose ane name-leet-style. Uise the chosen style for baith o the author and editor name-lists.

Pages with thir errors are automatically placed in Category:Pages with citations having redundant parameters.

Text "????" ignored

Help desk

Unlik mony Wikipedia templates, the Citation Style 1 and Citation Style 2 templates dae nae uise unnamed or positional parameters. When a citation contains text atween vertical bars and that text daes nae contain an equal sign (=), CS1|2 ignores the text and reports the error. This is true even whan the text is the name o a valid parameter.

This error can an aa be caused bi vertical bars that are pairt of URLs or titles. When vertical bars occur in URLs, replace each vertical bar with %7c. When vertical bars occur in parameter values that are nae URLs, replace each vertical bar with | or {{!}}.

Tae resolve this error, remove the extraneous text, add '=', add an appropriate parameter name frae the template you're using tae complete the parameter, or properly encode vertical bars in URLs and titles.

Pages with this error are automatically placed in Category:Pages with citations using unnamed parameters.

|trans-<param>= requires |<param>=

Help desk

Citation Style 1 and Citation Style 2 templates report this error whan the citation haes an Inglis translation o the title in |trans-title= or chapter title in |trans-chapter= but daes nae hae the oreeginal-language title in |title= or oreeginal-language chapter title in |chapter=.

Tae resolve this error, provide the oreeginal language title for |title= or chapter title for |title=. Consider adding |language= if nae already pairt o the citation.

Pages with this error are automatically placed in Category:CS1 errors: translated title.

Unknown parameter |xxxx= ignored

Help desk

Citation Style 1 and Citation Style 2 templates report this error whan the name portion o a parameter's |name=value pair is nae recognised as a valid name. teepically, this is caused bi spelling or capitalization errors.

With the auld-style citation templates, it wis possible tae include information within the template that wis simply ignored as unrecognized parameters. The Lua-based CS1|2 ingine daes nae ignore unrecognized parameters. The purpose o the citation is tae properly identify the soorce; nae act as a repository of notes and ancillary information.

CS1|2 template parameters are lawer case. CS1|2 will report this error whan the parameter's name contains uppercase letters (Xxxx, xxXx, XXXX) but the parameter's name is defined as lowercase (xxxx). The identifier parameters, lik |isbn=, |pmc=, |doi=, etc., can be either lawer case or upper case, but nae of mixed case (|isbn= or |ISBN= but nae |Isbn=). For common parameter misspellings, lik |pubisher= instead of |publisher=, CS1|2 will suggest a valid parameter name.

Tae resolve this error, replace the erroneous parameter name with a correct ane, possibly using the suggestit name. Ensure that the parameter's name is correctly spelled and that thare are no characters except spaces atween the parameter's name an the leadin vertical bar (|) or trailing equals sign (=). A leet of valid parameters can be foond bi consulting Help:Citation Style 1 or veesitin the description page o the specific template bein uised, sic as {{cite web}}, {{cite book}}, {{cite journal}}, etc. Consider muivin information associated with the unkent parameter intae an appropriate parameter or tae a section o the article's talk page for preservation.

Pages with this error are automatically placed in Category:Pages with citations using unsupported parameters.

Unsupported parameter(s) in cite arXiv

Help desk

{{cite arxiv}} uses a leemitit subset o the common Citation Style 1 parameters. This error message is emitted whan parameters nae in the {{cite arxiv}} subset occur in a {{cite arxiv}} template.

Tae resolve this error, remove the unsupported parameters. See Template:Cite arxiv for the complete leet of supported parameters.

Pages with this error are automatically placed in Category:CS1 errors: arXiv.

URL–wikilink conflict

Help desk

External links in a rendered citation are a combination of url-holding parameters, |url=, |chapter-url=, etc., with title-holding parameters, |title=, |chapter=, etc. Title-holding parameters mey be wikilinked tae anither Wikipedia article but nae whan thare is a matching url-holding parameter in the citation. When this condeetion occurs, the wikilink is suppressed, the wiki markup ignored, an the rendered citation links tae the external site.

Some templates will an aa cause this error if thay are pairt o a title-holding parameter. The error occurs whan the template produces wikilinked content. For example, {{lang}} templates output a wikilinked category. Templates in url-holding parameters mey an aa corrupt the citation's COinS metadata. As a general rule, avoid using templates in title-holding parameters unless you know that the template's affects are entirely visual ({{!}} an the lik).

This teep of error mey an aa occur in identifier-based templates ({{cite doi}}, etc.). When this happens, the error message is shawn in the article but the error is actually locatit in the identifier-based citation template.

Tae resolve this error, remove wikilinks frae title-holding parameters that are intendit tae be externally linked or remove the external URL, which will allou the internal wikilinks tae wirk as expected. If wikilink-producin templates are important tae the citation, muive them oot o the CS1 template but leave them inside the citation's <ref>...</ref> tags. Some o the functionality providit bi templates mey an aa be available throu CS1 parameters.

Tae resolve errors in identifier-based citation templates, the template must be edited tae correct the error. Exercise caution whan editing thir templates acause identifier-based citation templates are eften uised in multiple articles.

Pages with this error are automatically placed in Category:CS1 errors: URL–wikilink conflict.

Vancouver style error

Help desk

This error is reportit for citations that uise |name-list-format=vanc. Vancouver style restricts author or editor names tae the Latin alphabet. For the purposes of this test, Module:Citation/CS1 defines the Latin alphabet as the letters defined in the Unicode Latin character sets:

C0 Controls and Basic Latin (0041–005A, 0061–007A)

C1 Controls and Latin-1 Supplement (00C0–00D6, 00D8–00F6, 00F8–00FF)

Latin Extended-A (0100–017F)

Latin Extended-B (0180–01BF, 01C4–024F)

This error is an aa reportit whan a corporate or institutional author is listed in |vauthors= wioot proper delimiters. Corporate authors should be listed this way:

|vauthors=First Surname FM, Surname AB, ((Corporate or institutional Author)), Lastsurname XY

This error is an aa reportit whan mair nor twa initials are uised: in case of mair nor twa initials, leet anly the first twa.

While normally correct, whiles the names listed on a PMID page contain errors whan the author surname haes a lowercase nobiliary particle. For example, PMID 17726700 lists Magnus von Knebel Doeberitz as Doeberitz Mv which is nae correct. This author's name should be listed as |vauthors=von Knebel Doeberitz M.

Certain punctuation will be flagged as an error. For example, Unicode U+2019, right single quotation merk, causes an error acause it is nae a member o the Latin character sets identified abuin: |vauthors=Van’t Veer M. Replace this character with the straucht (or typewriter) apostrophe: |vauthors=Van't Veer M.

Tae resolve this error, Romanize author and editor names. Romanizing can result in twa-letter initials, for example, the Greek letter 'Θ' Romanizes tae 'Th'. When author names hae this kynd of initial, Module:Citation/CS1 can't know if this kynd of initial is a typo or a legitimate Romanized character sae it will emit the Vancouver error. Tae suppress the error efter determining that the twa-character initial is correct and nae a typo, treat the name as if it war a corporate name bi wrapping it in doubled parentheses: |vauthors=..., Tatarinov IuS, ... → |vauthors=..., ((Tatarinov IuS)), ...

Similarly, Cheenese hyphenated gien names mey appear in PubMed listings. For example: 'Wang Hsien-yu' mey be listed on PubMed as 'Wang Hy' which will result in a Vancouver error. When this occurs, an upon verification that sic names are correct, wrap them in doubled parentheses.

Pages with this error are automatically placed in Category:CS1 errors: Vancouver style.

<char> character in |<param>= at position n

Help desk

This error is reportit for citations with parameter values that contain invisible or non-printable characters kent as control characters; the error includes the poseetion at which the character can be foond. Module:Citation/CS1 detects parameter values that contain ony of thir characters:

replacement character, U+FFFD

hair space, U+200A

zero width space, U+200B

zero width joiner, U+200D

soft hyphen, U+00AD

horizontal tab, U+0009 (HT)

line feed, U+0010 (LF)

carriage return, U+0013 (CR)

delete character, U+007F (DEL)

C0 control, U+0000–U+001F (NULL–US)

C1 control, U+0080–U+009F (XXX–APC)

Tae resolve invisible-character errors, remove or replace the identified character. Because thir characters are maistly invisible, the error message identifies the character's poseetion in the parameter value counted frae the left. Space characters atween the assignment operator (the '=' sign) an the parameter value are nae counted.

Stripmarkers are special sequences of characters that MediaWiki inserts as a place-holder for certain xml-lik tags. Thir tags include <gallery>...</gallery>, <math>...</math>, <nowiki>...</nowiki>, <pre>...</pre>, and <ref>...</ref>. The stripmarkers are replaced with content afore the final page rendering. The module ignores math and nowiki stripmarkers.

Tae resolve stripmarker errors, remove or replace the identified tag. The error message identifies the stripmarker's poseetion in the parameter value counted frae the left. Space characters atween the assignment operator (the '=' sign) an the parameter value are nae counted.

Pages with this error are automatically placed in Category:CS1 errors: invisible characters.

|<param>-access= requires |<param>=

Help desk

This error is reportit whan an access level haes been specified for some external link, but the corresponding required parameter is missing or empty. The parameter can be ane of

access-level specifier required parameter

specifier	required parameter
|url-access=	|url=
|bibcode-access=	|bibcode=
|doi-access=	|doi=
|hdl-access=	|hdl=
|jstor-access=	|jsor=
|ol-access=	|ol=
|osti-access=	|osti=

Tae resolve this error, either provide a value for the parameter, or remove the access level specification.

Pages with this error are automatically placed in Category:CS1 errors: param-access.

Notes

References