Help:CS1 errors

This page describes the error messages reported by the cs1 and cs2 citations, what they mean, and how editors might resolve the errors. :Category:CS1 errors is the general errors category and :Category:CS1 maintenance is the general maintenance category.

Errors issued by Wikipedia's <ref> system, in which citation templates are typically embedded, can be found at Help:Cite errors.

Controlling error message display

By default, cs1 and cs2 error messages are visible to all readers and maintenance category messages are hidden from all readers.

To display maintenance messages, include the following text in your common Cascading Stylesheets|CSS page or your specific skin's CSS page (Special:MyPage/common.css|common.css and Special:MyPage/skin.css|skin.css respectively):

.mw-parser-output span.cs1-maint {display: inline;} /* display Citation Style 1 maintenance messages */

To display hidden-by-default error messages:

.mw-parser-output span.cs1-hidden-error {display: inline;} /* display hidden Citation Style 1 error messages */

Even with this CSS installed, older pages in Wikipedia's cache may not have been updated to show these error messages even though the page is listed in one of the tracking categories. A WP:NULLEDIT|null edit will resolve that issue.

To hide normally-displayed error messages:

.mw-parser-output span.cs1-visible-error {display: none;} /* hide Citation Style 1 error messages */

You can personalize the display of these messages (such as changing the color), but you will need to ask someone who knows CSS or at WP:VPT|the technical village pump if you do not understand how.<section end="show_all_messages_help_text" /><section end="show_error_messages_help_text" />

Most common errors

• #Cite <template> requires %7C<param>=, ~56k pages
• #Citation without a title of any form, ~40k pages
• #Bare URL without a title, ~28k pages
• #Check date values in: %7C<param1>=, %7C<param2>=, ..., ~13k pages
• #External link in %7C<param>=, ~11k pages

|access-date= requires |url=

The |access-date= (or its alias, |accessdate=) is the date that the online resource addressed by |url= was added to the article. If |access-date= has been included in the citation without |url= then this message appears. If the citation does not use a web link, then |access-date= is redundant and should be removed.

When the online resource has a publication or other fixed date associated with it, |access-date= is of limited value though may be useful in identifying an appropriate archived version of the resource. Without |url=, |access-date= is not considered useful.

To resolve this error, provide a value for |url= or remove |access-date=. Editors should try to determine why the citation has |access-date= without |url=. For example, the citation may never have had a |url=, or |url= may have been removed because it links to a site that violates the creator's copyright (see WP:COPYLINK), or because |url= was deemed to be dead. If the citation never had |url= or it was removed for copyright violations, remove |access-date=. When a dead |url= has been removed, restore the |url= and if possible repair it.

|archive-url= is malformed

Archive.org allows a variety of URLs to access snapshots of an archived page. Some of these 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

There are two forms of 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:

save command – the archive.org URL is the save command

path – web/ was expected but something else was found

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

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

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

When the archive.org URL has any of these errors, Module:Citation/CS1 does not link to archive.org and emits an appropriate error message.

To resolve this error, choose the URL of an appropriate snapshot from those held at archive.org. Search for the target URL.

|archive-url= requires |archive-date=

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

To resolve this error, provide a value for |archive-date= (see acceptable date formats in MOS:DATEFORMAT). For web resources archived at archive.org, the archival date can be found in the |archive-url=; for resources archived at webcitation.org, the cache date is included in the archive header.

|archive-url= requires |url=

A properly formatted citation that includes |archive-url= and |archive-date= requires |url=. When the citation includes |url-status=live, the ordering of elements in the rendered citation is changed to put the original URL first.

To resolve this error, provide a value for |url=. For web resources archived at archive.org, the original URL can be found in the |archive-url= value; for resources archived at webcitation.org, the original URL is included in the archive header.

|arxiv= required

cite arXiv requires one, but not both, of the identifier parameters |arxiv= or |eprint= to specify an arXiv identifier.

To resolve this error, ensure that the template has |arxiv= or |eprint= with a properly constructed value.

|asin-tld= requires |asin=

When |asin-tld= is used in a CS1|2 template, |asin= or |ASIN= (with value) must also be present.

To resolve this error, either add the missing ASIN or remove the 'broken' parameter

|biorxiv= required

cite bioRxiv requires the identifier parameter |biorxiv=.

To resolve this error, ensure that the template has |biorxiv= with a properly constructed value.

|chapter= ignored

cs1 templates cite web, cite news, cite journal, cite press release, cite podcast, cite newsgroup, as well as template citation when it uses |work= or any of its aliases, do not support |chapter= or the aliases |contribution=, |entry=, |article=, or |section=.

To resolve this error:

• use a more appropriate citation template, or
• place the content of the |chapter= parameter in |title=, or
• for {{cite news}}, |department= can be used to give the name of the newspaper's section, such as "Obituaries", or
• for citation, remove |work= or its aliases such as |website= and place their content in |title= if appropriate

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

This error is reported for citations with parameter values that contain invisible or non-printable characters known as control characters; the error includes the position at which the character can be found. Module:Citation/CS1 detects parameter values that contain any of these characters:

• non-breaking space, U+00A0
• soft hyphen, U+00AD
• replacement character, U+FFFD
• hair space, U+200A
• zero width space, U+200B
• zero width joiner, U+200D
• horizontal tab, U+0009 (HT)
• line feed, U+0010 (LF)
• carriage return, U+0013 (CR)
• delete character, U+007F (DEL)
• C0 and C1 control codes|C0 control, U+0000–U+001F (NULL–US)
• C0 and C1 control codes|C1 control, U+0080–U+009F (XXX–APC)

To resolve invisible-character errors, remove or replace the identified character. Most intentional white-space characters should be replaced with a normal space character (i.e. press your keyboard's space bar). See MOS:NBSP for guidance on insertion of intentional non-breaking spaces.

Because these characters are mostly invisible, the error message identifies the character's position in the parameter value counted from the left. Space characters between the assignment operator (the '=' sign) and the parameter value are not counted. If you move through the citation with the arrow keys then the cursor may stand still once at an invisible character, which can be removed with Delete or Backspace. If you copy-paste a string to the "Characters" field at https://r12a.github.io/app-conversion/ and click "View in UniView" then the position and name of all characters is shown.

Strip markers are special sequences of characters that MediaWiki inserts as a place-holder for certain xml-like tags. These tags include <gallery>...</gallery>, <math>...</math>, <nowiki>...</nowiki>, <pre>...</pre>, and <ref>...</ref>. The strip markers are replaced with content before the final page rendering. The module ignores math and nowiki strip markers.

To resolve strip marker errors, remove or replace the identified tag. The error message identifies the strip marker's position in the parameter value counted from the left. Space characters between the assignment operator (the '=' sign) and the parameter value are not counted when calculating the position.

Strip marker errors can also be caused by unsupported additional text or templates in parameter values for example, {{ISBN}} in |title=. Resolve the problem by moving the extraneous text outside of the citation template, or by removing the extraneous text or template markup, as appropriate.

Check |arxiv= value

When cs1 and cs2 templates contain |arxiv=, a test is done to see if the arXiv identifier conforms with the arXiv identifier scheme. The identifier is checked for a valid number of digits in the article id; valid year and month values; and properly-placed hyphens, slashes, and dots.

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

Check |asin= value

When cs1 and cs2 templates contain |asin=, a test is done to see if the ASIN identifier contains ten upper-case alphanumeric characters without punctuation or spaces and that if the first character is numeric, that the ASIN conforms to the rules for a ten-digit ISBN.

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

If the |asin= value is correct and all-numeric, use |isbn= instead and delete any |asin-tld= parameters.

Check |asin-tld= value

cs1 and cs2 templates contain a test for known |asin-tld= values to specify the top-level domain (TLD) of a given ASIN identifier link. The list of currently supported values is:

<section begin="asin-tld_values_list" />ae, au, br, ca, cn, de, es, fr, in, it, jp, mx, nl, pl, sa, se, sg, tr, uk<section end="asin-tld_values_list" />

It is not necessary to provide |asin-tld= to specify the default (United States). If you want to specify this condition explicitly, a pseudo-value of us can be given to denote this.

All these values are automatically resolved to the correct TLD following one of the schemes nn, com.nn, co.nn, z.nn, and com.

If an unsupported value is encountered, the template will issue this error message.

To resolve this error, ensure that the |asin-tld= value is correct.

If the value is correct, please report this at Help talk:Citation Style 1, so that it can be added to the list of supported values.

Check |bibcode= <message>

When cs1 and cs2 templates contain |bibcode=, a test is done to see if the bibcode identifier has the proper format. Bibcodes are expected to match these 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 a letter, ampersand, or dot (ampersand cannot directly precede a dot; &. (<message> = ''))

9 must be a letter or dot

10–18 must be a letter, digit, or dot

19 must be a letter or dot

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

Check |biorxiv= value

When cs1 and cs2 templates contain |biorxiv=, a test is done to see if the bioRxiv identifier has the proper form. There are two valid forms, each beginning with bioRxiv's doi directory indicator and registrant code (10.1101) and followed by:

six numeric characters without punctuation or spaces:

|biorxiv=10.1101/######

###### – 6-digit bioRxiv identifier

ymd format date prefix followed by six numeric characters without punctuation or spaces followed by optional version:

|biorxiv=10.1101/yyyy.mm.dd.######v# where:

yyyy.mm.dd. – represents a date no earlier than 11 December 2019 (2019.12.11.) and no later than tomorrow's date; date must be a valid date

###### – 6-digit bioRxiv identifier

v# – optional version indicator

A common error is to include the bioRxiv URL (https://dx.doi.org/10.1101/######}}).

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

Check |citeseerx= value

When cs1 and cs2 templates contain |citeseerx=, a test is done to see if the CiteSeerX identifier has the proper format. The expected identifier is the value assigned to the ?doi= query key in the URL of a CiteSeerX document. (This query key should not be confused with a Digital Object Identifier: it should not be input as |doi=.)

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

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

When cs1 and cs2 templates contain date-holding parameters, an automated test is done to see if the dates are real dates that comply with a Help:Citation_Style_1#Date_compliance_with_Wikipedia's_Manual_of_Style|subset of the date rules in Wikipedia's Manual of Style, specifically checking for violations of Wikipedia:Manual of Style/Dates and numbers#Dates and years|MOS:DATEFORMAT.

To resolve this error, ensure that the date is an actual date and that the date format follows the MOS:DATEFORMAT|Wikipedia Manual of Style's guidance on dates in the named parameter. See Help:CS1 errors#ExamplesOfUnacceptableDates|examples of unacceptable dates and how to fix them, below. Or, some conceptual issues to look for:

• impossible dates, such as 29 February 2011 (2011 was not a leap year)
• |access-date= must specify a day, not just 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 MOS:ALLCAPS for more detail that is not in MOS:DATEFORMAT|Wikipedia Manual of Style's guidance on dates)
• other unacceptable date formats listed in MOS:BADDATEFORMAT
• more than one date in a date-holding parameter
• years before 100 AD, including BCE/BC dates. Try using parameter |orig-date= instead.

See Help:Citation_Style_1#CS1_compliance_with_Wikipedia.27s_Manual_of_Style|Help: Citation Style 1 for information about limitations in the CS1 citation templates' handling of date formats. WP:DATERANGE|The MOS section on date ranges describes how to separate dates in a date range. Do not use  , –, or spaced ndash as these corrupt the metadata. To add an en dash, use the Help:CharInsert#Insert|CharInsert edit tool or see Wikipedia:How to make dashes. You may also use this one: –. A bot is often able to correct the separator, provided the overall format is unambiguous.

Future dates in |date= in CS1|2 citations are limited to current year + 1; that is, for 2024, citation dates in 2025 are acceptable but citation dates in 2026 and beyond are not.

Dates prior to 1582 are treated as Julian calendar dates. Dates from 1582 onward are treated as Gregorian calendar dates. The Julian calendar was used in some places until approximately 1923. Three Julian calendar dates in the overlap period, 29 February in the years 1700, 1800, and 1900, will cause this error message because those years are not leap years in the Gregorian calendar.

The access date (in |access-date=) is checked to ensure that it contains a full date (day, month, and year) and is between 15 January 2001 (the founding date of Wikipedia) and today's date plus one day, because it represents the date that an editor viewed a web-based source to verify a statement on Wikipedia. Because editors may be in time zones that are one day ahead of the UTC date, one extra day is accepted.

Examples of unacceptable dates and how to fix them

Issue	Unacceptable	Acceptable
Hyphen in date range (use en dash)	|date=2002-2003	|date=2002–2003
Slash in date range (use en dash)	|date=2002/2003 or |date=July/August 2003	|date=2002{}2003 or |date=July–August 2003
Hyphen in date range (use en dash)	|date=April-May 2004	|date=April–May 2004
Missing space around 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
Season capitalization	|date=spring 2011	|date=Spring 2011
Future date (typo)	|date=2102	|date=2012
Access date impossibly far in the past (typo)	|access-date=1 January 2001	|access-date=1 January 2010
Access date only 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=2002-03XX (Extended Date Time Format While normally correct, sometimes the names listed on a PMID page contain errors when the author surname has a lowercase nobiliary particle. For example, PMID lists Magnus von Knebel Doeberitz as Doeberitz Mv which is not 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 mark, causes an error because it is not a member of the Latin character sets identified above: |vauthors=Van’t Veer M. Replace this character with the straight (or typewriter) apostrophe: |vauthors=Van't Veer M. To resolve this error, Romanize author and editor names. Romanizing can result in two-letter initials, for example, the Greek letter 'Θ' Romanizes to 'Th'. When author names have this kind of initial, Module:Citation/CS1 can't know if this kind of initial is a typo or a legitimate Romanized character so it will emit the Vancouver error. To suppress the error after determining that the two-character initial is correct and not a typo, treat the name as if it were a corporate name by wrapping it in Help:Citation_Style_1#Accept-this-as-written_markup|doubled parentheses: |vauthors=..., Tatarinov IuS, ... → |vauthors=..., ((Tatarinov IuS)), ... Similarly, Chinese hyphenated given names may appear in PubMed listings. For example: 'Wang Hsien-yu' may be listed on PubMed as 'Wang Hy' which will result in a Vancouver error. When this occurs, and upon verification that such names are correct, wrap them in doubled parentheses. Specific rules for names: Surnames with hyphens and other punctuation in them Other surname rules Given names containing punctuation, a prefix, a preposition, or particle Degrees, titles, and honors before or after a personal name Designations of rank within a family, such as Jr and III Names appearing in non-roman alphabets (Cyrillic, Greek, Arabic, Hebrew, Korean) or character-based languages (Chinese, Japanese) Organizations as author CS1|2 does not obey the semicolon-as-separator rule. Separate corporate and organizational names from each other and from individual names with a comma; wrap corporate and organizational names in doubled parentheses as described above. |volume= has extra text The templates are responsible for static text rendered in the citation. When |volume= is used in a template, cs1|2 formats the volume value according to the style corresponding with the publication type associated with the used citation template. The templates emit this error message when some form of the word "volume" ("volume", "vol.") is found in the value assigned to |volume=. To resolve this error, remove the extraneous text from the parameter value. Notes <section end="notes_help_text" /><section begin="references_help_text" /> References <section end="references_help_text" />