Editing Help:CS1 errors (section)

==<span id="bad_ismn">Check |ismn= value</span>==
<section begin="bad_ismn_help_text" />{{help desk}}{{#invoke:Cs1 documentation support|help_text_error_messages|err_bad_ismn}}

{{cs1}} and {{cs2}} templates that contain {{para|ismn}} are checked to ensure that the [[ISMN]] is the proper length (thirteen digits), that the ISMN uses the correct optional separators (simple space or hyphen), and that the final [[check digit]] is correct according to the ISMN specification. Only one ISMN is allowed in this field because the whole {{para|ismn}} value is included in the citation's [[COinS]] [[metadata]]. See also [[Wikipedia:COinS]]. More than one ISMN, or characters that are not part of the ISMN, corrupt the COinS metadata. (If relevant, they can be specified using {{para|id|{{tlp|ISMN|...}}}} instead.)

To resolve this error, ensure that the {{para|ismn}} value is correct, that only one ISMN is used, that the proper optional separators are used, and that no other text is included. Make sure that the ISMN contains exactly 13 digits.

Pages with this error are automatically placed in {{#invoke:cs1 documentation support|help_text_cats|err_bad_ismn|pages=yes}}.<ref group="lower-alpha" name="categories" /><section end="bad_ismn_help_text" />