It is used to build and maintain lists of pages—primarily for the sake of the lists themselves and their use in article and category maintenance. It is not part of the encyclopedia's categorization scheme.
These categories are used to track, build and organize lists of pages needing "attention en masse" (for example, pages using deprecated syntax), or that may need to be edited at someone's earliest convenience.
These categories also serve to aggregate members of several lists or sub-categories into a larger, more efficient list (discriminated by classifications).
Typically, tracking categories are automatically populated by templates invoked in pages or by the MediaWiki software (see Special:TrackingCategories for an overview of the latter).
Administrators: Please do not delete this category as empty! This category may be empty occasionally or even most of the time.
Note that the ISBN hyphenation rule-base is a living document.
This is a maintenance category of articles with invalid ISBNs. It is often included by means of the template ((Please check ISBN)). If you fix an ISBN please remove the template or category from the article. Many article/ISBN problems are listed at WikiProject Check Wikipedia.
Reasons for invalid ISBNs
The main reasons for invalid ISBNs are -
not enough digits (could be 9 digits as used in Standard Book Numbering (SBN) or even an 8-digit ISSN - but be careful could be another reason)
invalid checksum
Also possible are
Invalid country code / publisher code (see the International ISBN Agency website)
invalid characters (,. etc.)
too long (but could be ISBN13 or even an ISBN13 with the digits "13" in front giving 15 digits, or "10" giving 12).
run-ons – "ISBN xxxxxxx-73" where the -73 isn't part of the ISBN
13 digit numbers that start with anything other than 978 or 979-10 (as of 2012).
15 digits starting with 977. In this case the next 7 are the ISSN (omitting its own check digit), the next 2 are used, for example, as a day of the week number; these are followed by a check digit, and the last two are an "issue number".
other...
ISBNs should not be listed because of
incorrect hyphenation
ISBN:
spaces instead of hyphens
These errors should simply be fixed.
The ISBN may have been incorrectly labelled invalid, but we have (to our surprise) found several examples where the publisher has put an invalid number on the book (see talk page for examples).
Note that just because a number has not been identified as invalid, it doesn't mean it corresponds to the book in question, or indeed any book.
Thirteen-digit ISBNs starting with 978
As of 2007, all publishers are expected to provide newly issued books with 13-digit ISBNs. Many books published between 2004 and 2006 have also been (explicitly) assigned ISBN 13s (they all have one based on the 10 digit ISBN, or 9 digit SBN). The effect of the new standards policies is that every recent book has a pair of equally-effective ISBNs, one ISBN-10 and an equivalent ISBN-13 that begins with 978. (Many current books have both ISBNs actually printed on the back cover). Books issued after 1 January 2007 are expected to have at least the ISBN-13 printed on them. For all books whose ISBN starts with 978- it is possible to uniquely refer to any book either by its ISBN-10 or its (equivalent) ISBN-13 and both numbers will continue to be reserved for use by that book by the local ISBN agency. Beginning with the 979 prefix, only the ISBN-13 will work or be meaningful for the given book since there will no longer be an equivalent ISBN-10. There are some plans to eventually phase out the use of ISBN 10s but the effective timing of that is still not clear.
Thirteen-digit ISBNs starting with 979
As of 2019 the following ranges of 979-... ISBNs have been encountered:[1]
