View source for Help:CS1 errors

{{Wikipedia how to}}

This page describes the error messages reported by [[Module:Citation/CS1]], what they mean, and suggests how editors might resolve the errors.

In 2013, Wikipedia editors upgraded the [[Help:Citation Style 1|Citation Style 1]] series of templates using the meta-template {{tlx|Citation/core}} into a single [[Lua (programming language)|Lua]] module as part of [[WP:LUA]]. The benefits of the upgrade are enhanced performance, reduced complexity and redundancy, and for the purposes of this page, improved error detection and reporting. 

==Controlling error message display==

During {{cs1}} development, many of the new error messages are hidden.  Hidden messages are exposed as development proceeds. Editors who wish to see all of the CS1 error messages can do so by updating their [[Special:MyPage/common.css|common]] or [[Special:MyPage/skin.css|skin]] CSS stylsheet to include: 
:{{code|.citation-comment {display: inline !important;}  /* show all Citation Style 1 error messages */||lang=css}}

Editors who do not wish to see any of the CS1 error messages can hide them all by updating their CSS stylesheet to include:
:{{code|.citation-comment {display: none !important;}  /* hide all Citation Style 1 error messages */ |lang=css}}

=={{anchor|accessdate_missing_url}}|accessdate= requires |url{{=}}==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=accessdate_missing_url_help_text /><span class="error"><code>|accessdate=</code> requires <code>|url=</code></span>

The {{para|accessdate}} parameter is used to identify the date that the web resource addressed by {{para|url}} was accessed. Without {{para|url}}, {{para|accessdate}} is meaningless. When {{para|url}} is omitted or left blank, the {{para|accessdate}} value is not displayed.

To resolve this error, provide a value for {{para|url}} or remove {{para|accessdate}}.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages using citations with accessdate and no URL | Category:Pages using citations with accessdate and no URL | [[:Category:Pages using citations with accessdate and no URL]]}}.<section end=accessdate_missing_url_help_text />

=={{anchor|archive_missing_url_not_dead}}|archiveurl= and |deadurl=no requires |url{{=}}==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=archive_missing_url_not_dead_help_text />{{hatnote|This error message should probably be removed. &#124;archiveurl{{=}} always requires &#124;url{{=}} regardless of the state of &#124;deadurl{{=}}}}
<span class="error"><code>|archiveurl=</code> and <code>|deadurl=no</code> requires <code>|url=</code></span>

Editors often preemptively locate an archived copy of a web resource and include the archive's url in a [[Help:Citation Style 1|CS1 citation]]. When they do, they may set {{para|deadurl|no}} to indicate that the original source url is still active. {{para|deadurl}} controls how the CS1 citation is formatted. Omitted or empty {{para|deadurl}} has the same effect as {{para|deadurl|yes}}.

To resolve this error, provide a value for {{para|url}}. For web resources archived at archive.org,<ref name="archive.org">{{cite web |url=http://www.archive.org |title=archive.org website}}</ref> the original url can be found in the {{para|archiveurl}} value; for resources archived at webcitation.org,<ref name="webcitation.org">{{cite web |url=http://www.webcitation.org |title=webcitation.org website}}</ref> the original url is included in the archive header.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with archiveurl citation errors | Category:Pages with archiveurl citation errors | [[:Category:Pages with archiveurl citation errors]]}}.<section end=archive_missing_url_not_dead_help_text />

=={{anchor|archive_missing_date}}|archiveurl= requires |archivedate{{=}}==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=archive_missing_date_help_text /><span class="error"><code>|archiveurl=</code> requires <code>|archivedate=</code></span>

{{para|archivedate}} identifies the date that the web resource was archived.

To resolve this error, provide a value for {{para|archivedate}}. For web resources archived at archive.org,<ref name="archive.org">{{cite web |url=http://www.archive.org |title=archive.org website}}</ref> the archival date can be found in the {{para|archiveurl}}; for resources archived at webcitation.org,<ref name="webcitation.org">{{cite web |url=http://www.webcitation.org |title=webcitation.org website}}</ref> the cache date is included in the archive header.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with archiveurl citation errors | Category:Pages with archiveurl citation errors | [[:Category:Pages with archiveurl citation errors]] }}.<section end=archive_missing_date_help_text />

=={{anchor|archive_missing_url}}|archiveurl= requires |url{{=}}==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=archive_missing_url_help_text /><span class="error"><code>|archiveurl=</code> requires <code>|url=</code></span>

A properly formatted citation that includes {{para|archiveurl}} and {{para|archivedate}} requires {{para|url}}. When the citation includes {{para|deadurl|no}}, the ordering of elements in the rendered citation is changed to put the original url first. This error message is not displayed by {{tlx|cite web}}.

To resolve this error, provide a value for {{para|url}}. For web resources archived at archive.org,<ref name="archive.org">{{cite web |url=http://www.archive.org |title=archive.org website}}</ref> the original url can be found in the {{para|archiveurl}} value; for resources archived at webcitation.org,<ref name="webcitation.org">{{cite web |url=http://www.webcitation.org |title=webcitation.org website}}</ref> the original url is included in the archive header.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with archiveurl citation errors | Category:Pages with archiveurl citation errors | [[:Category:Pages with archiveurl citation errors]]}}.<section end=archive_missing_url_help_text />

=={{anchor|bad_doi}}Check |doi= value==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=bad_doi_help_text /><span class="error">Check <code>|doi=</code> value</span>

When [[Help:Citation Style 1|CS1 citations]] contain {{para|doi}}, a test is done to see if the prefix portion of the [[Digital object identifier|DOI]] value contains the proper "<code>10.</code>" registry identifier.  Further validation of the DOI is not performed.

To resolve this error, ensure that the {{para|doi}} value is correct.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with DOI errors | Category:Pages with DOI errors | [[:Category:Pages with DOI errors]]}}.<section end=bad_doi_help_text />

=={{anchor|bad_isbn}}Check |isbn= value==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=bad_isbn_help_text /><span class="error">Check <code>|isbn=</code> value</span>

{{cs1}} templates that contain {{para|isbn}} are checked to ensure that the [[ISBN]] is the proper length (ten or thirteen digits) and validate the final [[check digit]] according to the ISBN specification. Only one ISBN is allowed in this field because the whole {{para|isbn}} value is included in the citation's [[COinS]] [[metadata]]. See also [[Wikipedia:COinS]]. More than one ISBN, or characters that are not part of the ISBN, corrupt the COinS metadata and will also corrupt the link to [[Special:BookSources]].

To resolve this error, ensure that the {{para|isbn}} value is correct, that only one ISBN is used, and that no other text is included. Use the 13-digit ISBN when it is available.

In very rare cases, publishers have released books with malformed ISBNs.  If you are certain that a non-conforming ISBN truly corresponds to the published work, then add {{para|ignore-isbn-error|true}} to the citation suppress the error message.  In many cases books may have been reissued with a corrected ISBN.  Use a corrected ISBN when possible.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with ISBN&#32;errors | Category:Pages with ISBN errors | [[:Category:Pages with ISBN errors]]}}.<section end=bad_isbn_help_text /><!-- See [[bugzilla:47049]] about {{FULLPAGENAME}}, category pagenames containing ISBN, and #ifeq: -->

=={{anchor|bad_ol}}Check |ol= value==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=bad_ol_help_text /><span class="error">Check <code>|ol=</code> value</span>

When [[Help:Citation Style 1|CS1 citations]] contain {{para|ol}}, a test is done to see if the last digit of the value is one of three characters: A (authors), M (books), or W (works). Further validation of the OL identifier is not performed.

To resolve this error, ensure that the {{para|ol}} value is correct.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with OL errors | Category:Pages with OL errors | [[:Category:Pages with OL errors]]}}.<section end=bad_ol_help_text />

=={{anchor|bad_url}}Check |url= scheme==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=bad_url_help_text /><span class="error">Check <code>|url=</code> scheme</span>

External links in [[Help:Citation Style 1|CS1 citations]] are made from two parts: the ''title'' ({{para|title}}, {{para|chapter}}, etc) and the ''url'' ({{para|url}}, {{para|chapter-url}} etc).  The {{para|url}} portion is required to have a [[URI scheme]].  Most typically the URI scheme is <code>http</code> though others may be used.

CS1 examines the values assigned to {{para|url}}-type parameters for a colon and the double forward slash ("//"). If either of these are not found then CS1 reports this error. Further validation of the URI scheme is not performed.

To resolve this error, ensure that the {{para|url}} value is correct.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with URL errors | Category:Pages with URL errors | [[:Category:Pages with URL errors]]}}.<section end=bad_url_help_text />

=={{anchor|displayauthors}}|displayauthors= suggested==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=displayauthors_help_text /><span class="error"><code>|displayauthors=</code> suggested</span>

Prior to the introduction of [[WP:LUA|Lua]]-based citations, the citation formatting templates were designed to support no more than nine authors.  If nine (or more) author parameters were specified, then the template would display eight author names followed by "et al." to indicate that the list had been truncated.  Some editors relied on this behavior to include the "et al." label.  For example:

{{cite compare |mode=book |last=First |last2=Second |last3=Third |last4=Fourth |last5=Fifth |last6=Sixth |last7=Seventh |last8=Eighth |last9=Ninth |last10=Tenth |last11=Eleventh |last12=Twelfth |title=Twelve Little Authors}}

The Lua-based citation templates can accommodate an arbitrarily large number of authors. As with the old templates, the Lua-based templates can explicitly include an "et al." label with the {{para|display-authors}} parameter.

{{cite compare |mode=book |last=First |last2=Second |last3=Third |last4=Fourth |last5=Fifth |last6=Sixth |last7=Seventh |last8=Eighth |last9=Ninth |last10=Tenth |last11=Eleventh |last12=Twelfth |title=Twelve Little Authors |display-authors=3}}

The old-style templates supported at most nine authors. The new Lua-based templates cannot know if editors created citations with exactly nine authors because there were only nine authors or, because old-style citations were limited to nine authors. This error message is reported by citations with exactly nine authors but without {{para|displayauthors}}. To preserve the behavior of old-style citations, Lua-based citations display "et al." in place of the ninth author.

To resolve this error, add the remaining authors to the citation or set {{para|displayauthors}} to <code>8</code> or some lesser value to truncate the author list.  If there are exactly nine authors, then set {{para|displayauthors}} to <code>9</code> or higher to display all nine authors without "et al."

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages using citations with old-style implicit et al. | Category:Pages using citations with old-style implicit et al. | [[:Category:Pages using citations with old-style implicit et al.]]}}<section end=displayauthors_help_text />

=={{anchor|displayeditors}}|displayeditors= suggested==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=displayeditors_help_text /><span class="error"><code>|displayeditors=</code> suggested</span>

Prior to the introduction of [[WP:LUA|Lua]]-based citations, the citation formatting templates were designed to support no more than four editors.  Specifically, if four (or more) editor parameters were specified, then the template would display three editor names followed by "et al." to indicate that the list had been truncated.  Some editors relied on this behavior to include the "et al." label.  For example:

{{cite compare |mode=book |editor-last=First |editor2-last=Second |editor3-last=Third |editor4-last=Fourth |editor5-last=Fifth |last=Milquetoast |first=Caspar |authorlink=Caspar Milquetoast |title=If You don't Think it Presumptuous of Me}}

The Lua-based citation templates can accommodate an arbitrarily large number of editors. The Lua-based templates can also explicitly include an "et al." label with the new {{para|displayeditors}} parameter, a parameter that was not available to the old-style templates. 

{{cite compare |mode=book |editor-last=First |editor2-last=Second |editor3-last=Third |editor4-last=Fourth |editor5-last=Fifth |last=Milquetoast |first=Caspar |authorlink=Caspar Milquetoast |title=If You don't Think it Presumptuous of Me |displayeditors=2}}

The old-style templates supported at most four editors. The new Lua-based templates cannot know if ''Wikipedia'' editors created citations with exactly four editors because there were only four editors or, because old-style citations were limited to four editors. This error message is reported by citations with exactly four editors but without {{para|displayeditors}}. To preserve the behavior of old-style citations, Lua-based citations display "et al." in place of the fourth editor.

To resolve this error, add the remaining editors to the citation or set {{para|displayeditors}} to <code>3</code> or some lesser value to truncate the editor list.  If there are exactly four editors, then set {{para|displayeditors}} to <code>4</code> or higher to display all four editors without including "et al."

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages using citations with old-style implicit et al. | Category:Pages using citations with old-style implicit et al. | [[:Category:Pages using citations with old-style implicit et al.]]}}<section end=displayeditors_help_text />

=={{anchor|empty_citation}}Empty citation==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=empty_citation_help_text /><span class="error">Empty citation</span>

"Empty" may mean that the [[Help:Citation Style 1|CS1 citation]] contains no recognizable parameter identifiers. For example this citation isn't "empty" because it contains usable information, but is "empty" because it doesn't contain the necessary parameter identifiers (in this case {{para|url}} and {{para|title}}) that tell {{tlx|cite web}} how to use the information that the citation does contain:
:<code><nowiki>{{cite web | http://www.foobar.com | The Foobar Bar}}</nowiki></code>

To resolve this error, add appropriate parameter identifiers.  Consider the possibility that the editor meant to use another template entirely.  Perhaps the editor used {{tlx|citation}} when the intent was to use {{tlx|citation needed}} or {{tlx|quote}}.  In these cases replace the CS1 citation with the appropriate template.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with empty citations | Category:Pages with empty citations | [[:Category:Pages with empty citations]]}}.<section end=empty_citation_help_text />

=={{anchor|extra_pages}}Extra |pages or |at==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=extra_pages_help_text /><span class="error">Extra <code>|pages</code> or <code>|at</code></span>

This error occurs when [[Help:Citation Style 1|CS1 citations]] attempt to simultaneously use more than one of the parameters: {{para|page}}, {{para|pages}}, or {{para|at}}.  Each of these parameters is meant to provide a different way of specifying the location of the cited content within a larger work, and only one of these parameters is displayed in any rendered citation.  According to their intended purpose, {{para|page}} should be used to specify a single page that is relevant to the cited content, {{para|pages}} should be used to specify a range or list of pages (e.g. 37–42) that are relevant, and {{para|at}} should be used to indicate a location in the larger work that is not a numbered page (e.g. "back cover").  Sometimes, editors misunderstand the meaning of {{para|pages}}, and attempt to use it to indicate the total number of pages in the resource.

When {{para|page}} is used with either or both of {{para|pages}} or {{para|at}}, only the {{para|page}} value is displayed.  Similarly, when {{para|pages}} is used with {{para|at}}, only the {{para|pages}} value is displayed.

To resolve this error, remove the inappropriate parameter.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations using conflicting page specifications | Category:Pages with citations using conflicting page specifications | [[:Category:Pages with citations using conflicting page specifications]]}}.<section end=extra_pages_help_text />

=={{anchor|format_missing_url}}|format= requires |url{{=}}==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=format_missing_url_help_text /><span class="error"><code>|format=</code> requires <code>|url=</code></span>

This error occurs when [[Help:Citation Style 1|CS1 citations]] use {{para|format}} without also providing a url for {{para|url}}.  The {{para|format}} parameter is used to specify the file format of a web resource (e.g. [[PDF]], [[Doc (computing)|DOC]], [[Microsoft Excel file format|XLS]], etc.).  In some cases an editor may have intended to use {{para|type}} to specify a kind of document (e.g. hard cover, paperback, pamphlet, etc.)  The {{para|format}} value is always displayed.

To resolve this error, remove {{para|format}} or define {{para|url}} or change {{para|format}} to {{para|type}}.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages using citations with format and no URL | Category:Pages using citations with format and no URL | [[:Category:Pages using citations with format and no URL]]}}.<section end=format_missing_url_help_text />

=={{anchor|trans_missing_chapter}}Missing or empty |chapter{{=}}==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=trans_missing_chapter_help_text /><span class="error">Missing or empty <code>|chapter=</code></span>

This error occurs when a [[Help:Citation Style 1|CS1 citation]] includes an English translation of a chapter title in {{para|trans_chapter}} without also including the original language chapter title in {{para|chapter}}.

To resolve this error, provide a value for {{para|chapter}}. Consider adding {{para|language}} if not already part of the citation.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations using translated terms without the original | Category:Pages with citations using translated terms without the original | [[:Category:Pages with citations using translated terms without the original]]}}.<section end=trans_missing_chapter_help_text />

=={{anchor|missing_title}}Missing or empty |title{{=}}==<!-- do not remove or change anchors without also changing links in Module:Citation/CS1 -->

There are four slightly different error conditions that can arise when [[Help:Citation Style 1|CS1 citations]] lack appropriate titles.  In each case, CS1 reports this error message. The necessary resolution may vary depending on the cause of the error.  The error message links to the appropriate description below.


{{anchor|bare_url_missing_title}}<section begin=bare_url_missing_title_help_text /><span class="error">Missing or empty <code>&#124;title=</code></span> – Bare URL without a title

All [[Lua (programming language)|Lua]]-based [[Help:Citation Style 1|CS1 citations]] except {{tlx|cite web}} report this error when a [[url]]-containing parameter, such as {{para|url}}, cannot be paired with an associated title. Because URLs are ugly and generally uninformative, it is expected that editors should provide a meaningful title for each url. In most cases this can be accomplished by using the {{para|title}} parameter.  However, this error may also occur with other less used url parameters, such as {{para|chapter-url}}, or when the {{para|title}} can not be linked due to conflicting {{para|titlelink}} parameter.

To resolve this error, provide an appropriate title for the URL, usually {{para|title}}.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations having bare URLs | Category:Pages with citations having bare URLs | [[:Category:Pages with citations having bare URLs]]}}.<section end=bare_url_missing_title_help_text />


{{anchor|citation_missing_title}}<section begin=citation_missing_title_help_text /><span class="error">Missing or empty <code>&#124;title=</code></span> – Citation without a title of any form

This error occurs for [[Help:Citation Style 1|CS1 citations]] when all of the associated title parameters are omitted or left blank.  Depending on the type of citation ({{tlx|cite web}}, {{tlx|cite book}}, {{tlx|cite journal}}, etc.), the possible title parameters may include {{para|title}}, {{para|chapter}}, {{para|article}}, {{para|journal}}, {{para|booktitle}}, and so forth.  At least one such title parameter must be provided for each citation.

Sometimes this error occurs because an editor has used a CS1 citation as a substitute for {{tlx|sfn}} or the {{tlx|harv}} family of [[Help:Shortened footnotes|shortened footnotes]].

To resolve this error, provide a value for {{para|title}} or, when used as a shortened footnote substitute, replace the CS1 citation with an appropriate shortened footnote template.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations lacking titles | Category:Pages with citations lacking titles | [[:Category:Pages with citations lacking titles]]}}.<section end=citation_missing_title_help_text />


{{anchor|trans_missing_title}}<section begin=trans_missing_title_help_text /><span class="error">Missing or empty <code>&#124;title=</code></span> – Translated title included without the original title

[[Help:Citation Style 1|CS1 citations]] report this error when the citation includes an English translation of the title in {{para|trans_title}} without also including the original language title in {{para|title}}.

To resolve this error, provide the original language title for {{para|title}}. Consider adding {{para|language}} if not already part of the citation.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations using translated terms without the original | Category:Pages with citations using translated terms without the original | [[:Category:Pages with citations using translated terms without the original]]}}.<section end=trans_missing_title_help_text />


{{anchor|cite_web_title}}<section begin=cite_web_title_help_text /><span class="error">Missing or empty <code>&#124;title=</code></span> – Web citation without a title

Only {{tlx|cite web}} citations that use {{para|url}} without an associated {{para|title}} report this error. Because [[URL]]s are ugly and generally uninformative, it is expected that editors should provide a meaningful title for each url.  When rendered these citations display the bare url followed by the error message.

To resolve this error, provide a value for {{para|title}}.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages using web citations with no title | Category:Pages using web citations with no title | [[:Category:Pages using web citations with no title]]}}.<section end=cite_web_title_help_text />

=={{anchor|cite_web_url}}Missing or empty |url{{=}}==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=cite_web_url_help_text /><span class="error">Missing or empty <code>|url=</code></span>

This is error message is reported only by {{tlx|cite web}} [[Help:Citation Style 1|CS1 citations]] where {{para|url}} is blank or omitted. The {{para|url}} parameter is required so that {{para|title}} can link to the web resource.

To resolve this error, provide a value for {{para|url}} or use a more appropriate CS1 citation.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages using web citations with no URL | Category:Pages using web citations with no URL | [[:Category:Pages using web citations with no URL]]}}.<section end=cite_web_url_help_text />

=={{anchor|redundant_parameters}}More than one of |param1=, |param2=, and |param3= specified==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=redundant_parameters_help_text /><span class="error">More than one of <code>|param1=</code>, <code>|param2=</code>, and <code>|param3=</code> specified</span>

This error occurs when a [[Help:Citation Style 1|CS1 citation]] includes more than one parameter that maps to the same meaning.  For example, {{para|author}}, {{para|last}}, and {{para|last1}} are all synonyms of each other, so no more than one of these parameters should ever be used in a single citation.

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

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations having redundant parameters | Category:Pages with citations having redundant parameters | [[:Category:Pages with citations having redundant parameters]]}}.<section end=redundant_parameters_help_text />

=={{anchor|text_ignored}}Text "????" ignored ==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=text_ignored_help_text /><span class="error">Text "????" ignored</span>

Unlike many Wikipedia templates, the [[Help:Citation Style 1|CS1 citations]] do not use unnamed or positional parameters. When a citation contains text between [[vertical bar]]s and that text does not contain an equal sign (=), CS1 ignores the text and reports the error. This is true even when the text is the name of a valid parameter.

This error can also caused by vertical bars that are part of URLs or titles. When vertical bars occur in URLs, replace each vertical bar with <code>%7c</code>. When vertical bars occur in parameter values that are not URLs, replace each vertical bar with <code>&amp;#124;</code>.

To resolve this error, remove the extraneous text, add '=', add an appropriate parameter name to complete the parameter, or properly encode vertical bars in URLs and titles.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations using unnamed parameters | Category:Pages with citations using unnamed parameters | [[:Category:Pages with citations using unnamed parameters]]}}.<section end=text_ignored_help_text />

=={{anchor|parameter_ignored}}Unknown parameter |????= ignored==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=parameter_ignored_help_text /><span class="error">Unknown parameter <code>????=</code> ignored</span>

[[Help:Citation Style 1|CS1 citations]]  report this error when the name portion of a parameter's {{para|name|value}} pair is not recognized as a valid name.  Typically this is caused by spelling or typographical errors.

To resolve this error, ensure that the parameter's name is correctly spelled and that there are no characters except spaces between the parameter's name and the leading vertical bar (|) or trailing equal sign (=).  A list of valid parameters can be found by consulting [[Help:Citation Style 1]] or visiting the description page of the specific template being used, such as {{tlx|cite web}}, {{tlx|cite book}}, {{tlx|cite journal}}, etc.

For frequently encountered errors, consider adding a suggested correction to the [[Module:Citation/CS1/Suggestions|list]] of common parameter misspellings.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations using unsupported parameters | Category:Pages with citations using unsupported parameters | [[:Category:Pages with citations using unsupported parameters]]}}.<section end=parameter_ignored_help_text />

=={{anchor|parameter_ignored_suggest}}Unknown parameter |xxxx= ignored (|yyyy= suggested)==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=parameter_case_help_text /><span class="error">Unknown parameter <code>|xxxx=</code> ignored (<code>|yyyy=</code> suggested)</span>

[[Help:Citation Style 1|CS1 citations]] report this error when the name portion of a parameter's {{para|name|value}}-pair is not recognized as a valid name. With very few exceptions CS1 citation parameters are lower case. CS1 will report this error when the parameter's name contains uppercase letters ({{!xt|Xxxx, xxXx, XXXX}}) but the parameter's name is defined as lowercase ({{xt|xxxx}}). Some parameters, like {{para|isbn}} can be either lowercase or uppercase, but not of mixed case ({{xt|{{para|isbn}}}} or {{xt|{{para|ISBN}}}} but not {{!xt|{{para|Isbn}}}}). CS1 will also report this error when the parameter's name matches a name in the [[Module:Citation/CS1/Suggestions|list]] of common parameter misspellings (found {{para|acessdate}} but expected {{para|accessdate}}).

CS1 will offer a suggested parameter name from the list of valid parameters or from the list of common parameter misspellings.

To resolve this error, replace the erroneous parameter name with a correct one, possibly using the suggested name.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations using unsupported parameters | Category:Pages with citations using unsupported parameters | [[:Category:Pages with citations using unsupported parameters]]}}.<section end=parameter_case_help_text />

=={{anchor|wikilink_in_url}}Wikilink embedded in URL title==<!-- do not remove or change anchor without also changing links in Module:Citation/CS1 -->
<section begin=wikilink_in_url_help_text /><span class="error">Wikilink embedded in URL title</span>

Fields such as {{para|title}}, {{para|chapter}}, {{para|article}}, or {{para|booktitle}} may include a [[wikilink]] to another Wikipedia article, or they may include a link to an external site using {{para|url}} or a similar parameter, but they cannot include both.

To resolve this error, remove wikilinks that occur within fields that are intended to be externally linked. Or, remove the external URL, which will allow the internal wikilinks to work as expected. [[Template:Lang|Language templates]] will also cause this error: use {{para|language}} with the plain name of the language instead.

Pages with this error are automatically placed in {{#ifeq: {{FULLPAGENAME}} | Category:Pages with citations having wikilinks embedded in URL titles | Category:Pages with citations having wikilinks embedded in URL titles | [[:Category:Pages with citations having wikilinks embedded in URL titles]]}}.<section end=wikilink_in_url_help_text />

==References==
{{reflist}}

{{Wikipedia referencing}}
{{Help navigation}}