International Standard Book Number
A 13-digit ISBN, 978-3-16-148410-0, as represented by an EAN-13 bar code
|Managing organisation||International ISBN Agency|
|Number of digits||13 (formerly 10)|
|Check digit||Weighted sum|
An ISBN is assigned to each edition and variation (except reprintings) of a book. For example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, and 10 digits long if assigned before 2007. The method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country.
The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering (SBN) created in 1966. The 10-digit ISBN format was developed by the International Organization for Standardization (ISO) and was published in 1970 as international standard ISO 2108 (the SBN code can be converted to a ten digit ISBN by prefixing it with a zero).
Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure; however, this can be rectified later.
Another identifier, the International Standard Serial Number (ISSN), identifies periodical publications such as magazines; and the International Standard Music Number (ISMN) covers for musical scores.
- 1 History
- 2 Overview
- 3 Check digits
- 4 EAN format used in barcodes, and upgrading
- 5 See also
- 6 Notes and references
- 7 External links
The Standard Book Numbering (SBN) code is a numeric commercial book identifier based upon 9-digits created by Gordon Foster, Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers WHSmith and others in 1965. The ISBN configuration of recognition was generated in 1967 by David Whitaker (regarded as the "Father of the ISBN") and Emery Koltay (who later became director of the U.S. ISBN agency, Bowker).
The 10-digit ISBN format was developed by the International Organization for Standardization (ISO) and was published in 1970 as international standard ISO 2108. The United Kingdom continued to use the 9-digit SBN code until 1974. ISO has appointed the International ISBN Agency as the registration authority for ISBN worldwide and the ISBN Standard is developed under the control of ISO Technical Committee 46/Subcommittee 9 TC 46/SC 9. The ISO on-line facility only refers back to 1978.
An SBN may be converted to an ISBN by prefixing the digit "0". For example, the second edition of Mr. J. G Reeder Returns published by Hodder in 1965 has "SBN 340 01381 8" - 340 indicating the publisher, 01381 their serial number, and 8 being the check digit, this can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated.
An ISBN is assigned to each edition and variation (except reprintings) of a book. For example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, and 10 digits long if assigned before 2007. An International Standard Book Number consists of 4 parts (if it is a 10 digit ISBN) or 5 parts (for a 13 digit ISBN):
- for a 13-digit ISBN, a prefix element – a GS1 prefix: so far 978 or 979 have been made available by GS1,
- the registration group element, (language-sharing country group, individual country or territory)
- the registrant element,
- the publication element, and
- a checksum character or check digit.
A 13-digit ISBN can be separated into its parts (prefix element, registration group, registrant, publication and check digit), and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts (registration group, registrant, publication and check digit) of a 10-digit ISBN is also done with either hyphens or spaces. Figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits.
How ISBNs are issued
ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for that country or territory regardless of the publication language. The ranges of ISBNs assigned to any particular country are based on the publishing profile of the country concerned, and so the ranges will vary depending on the number of books and the number, type, and size of publishers that are active. Some ISBN registration agencies are based in national libraries or within ministries of culture and thus may receive direct funding from government to support their services. In other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the stated purpose of encouraging Canadian culture. In the United Kingdom, United States, and some other countries, where the service is provided by non-government-funded organisations, the issuing of ISBNs requires payment of a fee.
Australia: ISBNs are issued by the commercial library services agency Thorpe-Bowker, and prices range from $42 for a single ISBN (plus a $55 registration fee for new publishers) to $2,890 for a block of 1,000 ISBNs. Access is immediate when requested via their website.
Canada: Library and Archives Canada, a government agency, is responsible for issuing ISBNs, and there is no cost. Works in French are issued an ISBN by the Bibliothèque et Archives nationales du Québec.
India: The Raja Rammohun Roy Library Foundation (RRRLF), part of the Ministry of Culture, is responsible for registration of Indian publishers, authors, universities, institutions, and government departments that are responsible for publishing books.
Italy: The privately held company EDISER srl, owned by Associazione Italiana Editori (Italian Publishers Association) is responsible for issuing ISBNs. The original national prefix 978-88 is reserved for publishing companies, starting at €49 for a ten-codes block while a new prefix 979-12 is dedicated to self-publishing authors, at a fixed price of €25 for a single code.
Pakistan: The National Library of Pakistan is responsible for ISBN registrations for Pakistani publishers, authors, universities, institutions, and government departments that are responsible for publishing books.
South Africa: The National Library of South Africa is responsible for ISBN issuance for South African publishing institutions and authors.
United Kingdom and Republic of Ireland: The privately held company Nielsen Book Services Ltd, part of Nielsen Holdings N.V., is responsible for issuing ISBNs in blocks of 10, 100 or 1000. Prices start from £120 (plus VAT) for the smallest block on a standard turnaround of ten days.
United States: In the United States, the privately held company R.R. Bowker issues ISBNs. There is a charge that varies depending upon the number of ISBNs purchased, with prices starting at $125.00 for a single number. Access is immediate when requested via their website.
Publishers and authors in other countries obtain ISBNs from their respective national ISBN registration agency. A directory of ISBN agencies is available on the International ISBN Agency website.
Registration group identifier
The registration group identifier is a 1- to 5-digit number that is valid within a single prefix element (i.e. one of 978 or 979). Registration group identifiers have primarily been allocated within the 978 prefix element. The single-digit group identifiers within the 978 prefix element are: 0 or 1 for English-speaking countries; 2 for French-speaking countries; 3 for German-speaking countries; 4 for Japan; 5 for Russian-speaking countries; and 7 for People's Republic of China. An example 5-digit group identifier is 99936, for Bhutan. The allocated group IDs are: 0–5, 600–621, 7, 80–94, 950–989, 9926–9989, and 99901–99976. Books published in rare languages typically have longer group identifiers.
Within the 979 prefix element, the registration group identifier 0 is reserved for compatibility with International Standard Music Numbers (ISMNs), but such material is not actually assigned an ISBN. The registration group identifiers within prefix element 979 that have been assigned are 10 for France, 11 for the Republic of Korea, and 12 for Italy.
The original 9-digit standard book number (SBN) had no registration group identifier, but affixing a zero (0) as a prefix to a 9-digit SBN creates a valid 10-digit ISBN.
The national ISBN agency assigns the registrant element (cf. Category:ISBN agencies) and an accompanying series of ISBNs within that registrant element to the publisher; the publisher then allocates one of the ISBNs to each of its books. In most countries, a book publisher is not required by law to assign an ISBN; however, most book stores only handle ISBN bearing merchandise.
A listing of more than 900,000 assigned publisher codes is published, and can be ordered in book form (€1399, US$1959). The web site of the ISBN agency does not offer any free method of looking up publisher codes. Partial lists have been compiled (from library catalogs) for the English-language groups: identifier 0 and identifier 1.
Publishers receive blocks of ISBNs, with larger blocks allotted to publishers expecting to need them; a small publisher may receive ISBNs of one or more digits for the registration group identifier, several digits for the registrant, and a single digit for the publication element. Once that block of ISBNs is used, the publisher may receive another block of ISBNs, with a different registrant element. Consequently, a publisher may have different allotted registrant elements. There also may be more than one registration group identifier used in a country. This might occur once all the registrant elements from a particular registration group have been allocated to publishers.
By using variable block lengths, registration agencies are able to customise the allocations of ISBNs that they make to publishers. For example, a large publisher may be given a block of ISBNs where fewer digits are allocated for the registrant element and many digits are allocated for the publication element; likewise, countries publishing many titles have few allocated digits for the registration group identifier and many for the registrant and publication elements. Here are some sample ISBN-10 codes, illustrating block length variations.
|ISBN||Country or area||Publisher|
|80-902734-1-6||Czech Republic; Slovakia||Taita Publishers|
|85-359-0277-5||Brazil||Companhia das Letras|
|1-84356-028-3||English-speaking area||Simon Wallenberg Press|
|0-8044-2957-X||English-speaking area||Frederick Ungar|
|0-85131-041-9||English-speaking area||J. A. Allen & Co.|
|0-9752298-0-X||English-speaking area||KT Publishing|
Pattern for English language ISBNs
English-language registration group elements are 0 and 1 (2 of more than 220 registration group elements). These two registration group elements are divided into registrant elements in a systematic pattern, which allows their length to be determined, as follows:
|0 – Registration group element||1 – Registration group element||Total
A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary check bit. It consists of a single digit computed from the other digits in the number. The method for the ten digit code is an extension of that for SBNs, the two systems are compatible, and SBN prefixed with "0" will give the same check-digit as without - the digit is base eleven, and can be 0-9 or X. The system for thirteen digit codes is not compatible and will, in general, give a different check digit from the corresponding 10 digit ISBN, and does not provide the same protection against transposition. This is because the thirteen digit code was required to be compatible with the EAN format, and hence could not contain an "X".
ISBN-10 check digits
The 2001 edition of the official manual of the International ISBN Agency says that the ISBN-10 check digit – which is the last digit of the ten-digit ISBN – must range from 0 to 10 (the symbol X is used for 10), and must be such that the sum of all the ten digits, each multiplied by its (integer) weight, descending from 10 to 1, is a multiple of 11.
For example, for an ISBN-10 of 0-306-40615-2:
Formally, using modular arithmetic, we can say:
It is also true for ISBN-10's that the sum of all the ten digits, each multiplied by its weight in ascending order from 1 to 10, is a multiple of 11. For this example:
Formally, we can say:
The two most common errors in handling an ISBN (e.g., typing or writing it) are a single altered digit or the transposition of adjacent digits. It can be proved that all possible valid ISBN-10's have at least two digits different from each other. It can also be proved that there are no pairs of valid ISBN-10's with eight identical digits and two transposed digits. (These are true only because the ISBN is less than 11 digits long, and because 11 is a prime number.) The ISBN check digit method therefore ensures that it will always be possible to detect these two most common types of error, i.e. if either of these types of error has occurred, the result will never be a valid ISBN – the sum of the digits multiplied by their weights will never be a multiple of 11. However, if the error occurs in the publishing house and goes undetected, the book will be issued with an invalid ISBN.
In contrast, it is possible for other types of error, such as two altered non-transposed digits, or three altered digits, to result in a valid ISBN number (although it is still unlikely).
ISBN-10 check digit calculation
Modular arithmetic is convenient for calculating the check digit using modulus 11. Each of the first nine digits of the ten-digit ISBN – excluding the check digit, itself – is multiplied by a number in a sequence from 10 to 2, and the remainder of the sum, with respect to 11, is computed. The resulting remainder, plus the check digit, must equal a multiple of 11 (either 0 or 11). Therefore, the check digit is (11 minus the remainder of the sum of the products modulo 11) modulo 11. Taking the remainder modulo 11 a second time accounts for the possibility that the first remainder is 0. Without the second modulo operation the calculation could end up with 11 – 0 = 11 which is invalid. (Strictly speaking the first "modulo 11" is unneeded, but it may be considered to simplify the calculation.)
For example, the check digit for an ISBN-10 of 0-306-40615-? is calculated as follows:
Thus the check digit is 2, and the complete sequence is ISBN 0-306-40615-2. The value required to satisfy this condition might be 10; if so, an 'X' should be used.
ISBN-13 check digit calculation
The 2005 edition of the International ISBN Agency's official manual describes how the 13-digit ISBN check digit is calculated. The ISBN-13 check digit, which is the last digit of the ISBN, must range from 0 to 9 and must be such that the sum of all the thirteen digits, each multiplied by its (integer) weight, alternating between 1 and 3, is a multiple of 10.
Formally, using modular arithmetic, we can say:
The calculation of an ISBN-13 check digit begins with the first 12 digits of the thirteen-digit ISBN (thus excluding the check digit itself). Each digit, from left to right, is alternately multiplied by 1 or 3, then those products are summed modulo 10 to give a value ranging from 0 to 9. Subtracted from 10, that leaves a result from 1 to 10. A zero (0) replaces a ten (10), so, in all cases, a single check digit results.
For example, the ISBN-13 check digit of 978-0-306-40615-? is calculated as follows:
s = 9×1 + 7×3 + 8×1 + 0×3 + 3×1 + 0×3 + 6×1 + 4×3 + 0×1 + 6×3 + 1×1 + 5×3 = 9 + 21 + 8 + 0 + 3 + 0 + 6 + 12 + 0 + 18 + 1 + 15 = 93 93 / 10 = 9 remainder 3 10 – 3 = 7
Thus, the check digit is 7, and the complete sequence is ISBN 978-0-306-40615-7.
Formally, the ISBN-13 check digit calculation is:
This check system – similar to the UPC check digit formula – does not catch all errors of adjacent digit transposition. Specifically, if the difference between two adjacent digits is 5, the check digit will not catch their transposition. For instance, the above example allows this situation with the 6 followed by a 1. The correct order contributes 3×6+1×1 = 19 to the sum; while, if the digits are transposed (1 followed by a 6), the contribution of those two digits will be 3×1+1×6 = 9. However, 19 and 9 are congruent modulo 10, and so produce the same, final result: both ISBNs will have a check digit of 7. The ISBN-10 formula uses the prime modulus 11 which avoids this blind spot, but requires more than the digits 0-9 to express the check digit.
Additionally, if the sum of the 2nd, 4th, 6th, 8th, 10th, and 12th digits is tripled then added to the remaining digits (1st, 3rd, 5th, 7th, 9th, 11th, and 13th), the total will always be divisible by 10 (i.e., end in 0).
ISBN-10 to ISBN-13 conversion
The conversion is quite simple as one only needs to prefix "978" to the existing number and calculate the new checksum using the ISBN-13 algorithm.
Errors in usage
Publishers and libraries have varied policies about the use of the ISBN check digit. Publishers sometimes fail to check the correspondence of a book title and its ISBN before publishing it; that failure causes book identification problems for libraries, booksellers, and readers. For example, ISBN 0-590-76484-5 is shared by two books – Ninja gaiden® : a novel based on the best-selling game by Tecmo (1990) and Wacky Laws (1997), both published by Scholastic.
Most libraries and booksellers display the book record for an invalid ISBN issued by the publisher. The Library of Congress catalogue contains books published with invalid ISBNs, which it usually tags with the phrase "Cancelled ISBN". However, book-ordering systems such as Amazon.com will not search for a book if an invalid ISBN is entered to its search engine. OCLC often indexes by invalid ISBNs, if the book is indexed in that way by a member library.
Only the term "ISBN" should be used; the terms "eISBN" and "e-ISBN" have historically been sources of confusion and should be avoided. If a book exists in one or more digital (e-book) formats, each of those formats must have its own ISBN. In other words, each of the three separate EPUB, Amazon Kindle, and PDF formats of a particular book will have its own specific ISBN. They should not share the ISBN of the paper version, and there is no generic "eISBN" which encompasses all the e-book formats for a title.
EAN format used in barcodes, and upgrading
Currently the barcodes on a book's back cover (or inside a mass-market paperback book's front cover) are EAN-13; they may have a separate barcode encoding five digits for the currency and the recommended retail price. For 10 digit ISBNs, the number "978", the Bookland "country code", is prefixed to the ISBN in the barcode data, and the check digit is recalculated according to the EAN13 formula (modulo 10, 1x and 3x weighting on alternate digits).
Partly because of an expected shortage in certain ISBN categories, the International Organization for Standardization (ISO) decided to migrate to a thirteen-digit ISBN (ISBN-13). The process began 1 January 2005 and was planned to conclude 1 January 2007. As of 2011, all the 13-digit ISBNs began with 978. As the 978 ISBN supply is exhausted, the 979 prefix was introduced. Part of the 979 prefix is reserved for use with the Musicland code for musical scores with an ISMN. 10 digit ISMN codes differed visually as they began with an "M" letter; the bar code represents the "M" as a zero (0), and for checksum purposes it counted as a 3. All ISMNs are now 13 digits commencing 979-0; 979-1 to 979-9 will be used by ISBN.
Publisher identification code numbers are unlikely to be the same in the 978 and 979 ISBNs, likewise, there is no guarantee that language area code numbers will be the same. Moreover, the ten-digit ISBN check digit generally is not the same as the thirteen-digit ISBN check digit. Because the GTIN-13 is part of the Global Trade Item Number (GTIN) system (that includes the GTIN-14, the GTIN-12, and the GTIN-8), the 13-digit ISBN falls within the 14-digit data field range.
Barcode format compatibility is maintained, because (aside from the group breaks) the ISBN-13 barcode format is identical to the EAN barcode format of existing ISBN 10s. So, migration to an EAN-based system allows booksellers the use of a single numbering system for both books and non-book products that is compatible with existing ISBN based data, with only minimal changes to information technology systems. Hence, many booksellers (e.g., Barnes & Noble) migrated to EAN barcodes as early as March 2005. Although many American and Canadian booksellers were able to read EAN-13 barcodes before 2005, most general retailers could not read them. The upgrading of the UPC barcode system to full EAN-13, in 2005, eased migration to the ISBN-13 in North America.
- ASIN (Amazon Standard Identification Number)
- CODEN (serial publication identifier currently used by libraries; replaced by the ISSN for new works)
- DOI (Digital Object Identifier)
- ESTC (English Short Title Catalogue)
- ETTN (Electronic Textbook Track Number)
- ISAN (International Standard Audiovisual Number)
- ISMN (International Standard Music Number)
- ISWC (International Standard Musical Work Code)
- ISRC (International Standard Recording Code)
- ISSN (International Standard Serial Number)
- ISTC (International Standard Text Code)
- ISWN (International Standard Wine Number)
- LCCN (Library of Congress Control Number)
- List of group-0 ISBN publisher codes
- List of group-1 ISBN publisher codes
- OCLC number (Online Computer Library Center number)
- Registration authority
- SICI (Serial Item and Contribution Identifier)
- Special:Booksources, Wikipedia's ISBN search page
- VD 16 (Verzeichnis der im deutschen Sprachbereich erschienenen Drucke des 16. Jahrhunderts)(in English: Bibliography of Books Printed in the German Speaking Countries of the Sixteenth Century)
- VD 17 (Verzeichnis der im deutschen Sprachraum erschienenen Drucke des 17. Jahrhunderts)(in English: Bibliography of Books Printed in the German Speaking Countries of the Seventeenth Century)
Notes and references
- Occasionally, publishers erroneously assign an ISBN to more than one title—the first edition of The Ultimate Alphabet and The Ultimate Alphabet Workbook have the same ISBN, 0-8050-0076-3. Conversely, books are published with several ISBNs: A German second-language edition of Emil und die Detektive has the ISBNs 87-23-90157-8 (Denmark), 0-8219-1069-8 (United States), 91-21-15628-X (Sweden), 0-85048-548-7 (United Kingdom) and 3-12-675495-3 (Germany).
- In some cases, books sold only as sets share ISBNs. For example, the Vance Integral Edition used only two ISBNs for 44 books.
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- Bradley, Philip (1992). " PDF (245KB). The Indexer. 18 (1): 25–26.
- Foster, Gordon (1966). "INTERNATIONAL STANDARD BOOK NUMBERING (ISBN) SYSTEM original 1966 report". informaticsdevelopmentinstitute.net. Archived from the original on 30 April 2011. Retrieved 20 April 2014.
- "ISBN History". isbn.org. 20 April 2014. Archived from the original on 20 April 2014. Retrieved 20 April 2014.
- Information Standards Quarterly (PDF) 8 (3), ISO, July 1996, p. 12
- US ISBN Agency. "Bowker.com – Products". Commerce.bowker.com. Retrieved 2015-06-11.
- Gregory, Daniel. "ISBN". PrintRS. Retrieved 2015-06-11.
- ISO 2108:1978 (PDF), ISO
- TC 46/SC 9, Frequently Asked Questions about the new ISBN standard from ISO, CA: LAC‐BAC
- PDF (548 KB)
- International ISBN Agency (2012). ISBN Users' manual (PDF). isbn-international.org (Sixth International ed.). ISBN 978-92-95055-02-5. Archived (PDF) from the original on 29 April 2014. Retrieved 29 April 2014.
- Some books have several codes in the first block: e.g. A. M. Yaglom's Correlation Theory..., published by Springer Verlag, has two ISBNs, 0-387-96331-6 and 3-540-96331-6. Though Springer's 387 and 540 codes are different for English (0) and German (3); the same item number 96331 produces the same check digit: 6. Springer uses 431 as their publisher code for Japanese (4) and 4-431-96331-? would also have check digit ? = 6. Other Springer books in English have publisher code 817, and 0-817-96331-? would also get check digit ? = 6. This suggests special considerations were made for assigning Springer's publisher codes, as random assignments of different publisher codes would not lead the same item number to get the same check digit every time. Finding publisher codes for English and German, say, with this effect amounts to solving a linear equation in modular arithmetic.
- The international ISBN agency's ISBN User's Manual says: "The ten-digit number is divided into four parts of variable length, which must be separated clearly, by hyphens or spaces" although omission of separators is permitted for internal data processing. If present, hyphens must be correctly placed; see ISBN hyphenation definition. The actual definition for hyphenation contains more than 220 different registration group elements with each one broken down into a few to several ranges for the length of the registrant element (more than 1,000 total). The document defining the ranges, listed by agency, is 29 pages.
- "Bowker -- ISBN". Thorpe-Bowker. 5 Jan 2009. Retrieved 29 March 2012.
- "TABELA DE PREÇOS DOS SERVIÇOS". Biblioteca Nacional, Government of Brazil. Retrieved 8 September 2015.
- "Book Promotion". Ministry of Human Resource Development, Government of India. Retrieved 11 May 2014.
- "ISBN – Chi siamo e contatti" [ISBN – Who we are and contacts] (in Italian). EDISER srl. Retrieved 3 January 2015.
- "ISBN – Tariffe Servizi ISBN" [ISBN Service Tariffs] (in Italian). EDISER srl. Retrieved 3 January 2015.
- "http://www.isbn.nielsenbook.co.uk/controller.php?page=123". Nielsen UK ISBN Agency. Retrieved 2 January 2015.
- "Bowker -- ISBN". RR Bowker. 8 March 2013. Retrieved 8 March 2013.
- "ISBN Ranges". isbn-international.org. 29 April 2014. Select the format you desire and click on the Generate button. Archived from the original on 29 April 2014. Retrieved 29 April 2014.
- See a complete list of group identifiers. ISBN.org sometimes calls them group numbers. Their table of identifiers now refers to ISBN prefix ranges, which must be assumed to be group identifier ranges.
- Hailman, Jack Parker (2008). Coding and redundancy: man-made and animal-evolved signals. Harvard University Press. p. 209. ISBN 978-0-674-02795-4.
- International ISBN Agency (5 December 2014). "International ISBN Agency – Range Message (pdf sorted by prefix)" (PDF). isbn-international.org. p. 29. Retrieved 15 December 2014.
- See Publisher's International ISBN Directory
- Splane, Lily (2002). The Book Book: A Complete Guide to Creating a Book on Your Computer. Anaphase II Publishing. p. 37. ISBN 978-0-945962-14-4.
- "ISBN Ranges". isbn-international.org. International ISBN Agency. September 15, 2014. Retrieved September 15, 2014.
- "ISBN Users' Manual – 4. Structure of ISBN". Isbn.org. Archived from the original on 22 May 2013. Retrieved 2013-05-27.
- For example I'saka: a sketch grammar of a language of north-central New Guinea. Pacific Linguistics. ISBN "0-85883-554-4".
- PDF (284 KB) Archived April 29, 2014 at the Wayback Machine
- Lorimer, Rowland; Shoichet, Jillian; Maxwell, John W. (2005). Book Publishing I. CCSP Press. p. 299. ISBN 978-0-9738727-0-5.
- 020 – International Standard Book Number (R) – MARC 21 Bibliographic – Full. Library of Congress.
- sellbox.com, Retrieved, October 9, 2014
- Frequently asked questions, US: ISBN, 12 March 2014 — including a detailed description of the EAN-13 format.
- "ISBN", ISO TC49SC9 (FAQ), CA: Collections
- "Are You Ready for ISBN-13?", Standards, ISBN
- "WorldCat Web service: xISBN OCLC – WorldCat Affiliate tools]: xOCLCNUM". Xisbn.worldcat.org. Retrieved 2013-05-27.
|Wikidata has a property, P957, for ISBN-10 (see uses)|
|Wikidata has a property, P212, for ISBN-13 (see uses)|
- ISO 2108:2005 at www.iso.org
- "Are You Ready for ISBN-13?". R.R. Bowker LLC.
- Description of the ISBN to EAN upgrade process at bookweb.org
- International ISBN Agency—coordinates and supervises the worldwide use of the ISBN system.
- Numerical List of Group Identifiers List of language/region prefixes
- Free conversion tool: ISBN-10 to ISBN-13 & ISBN-13 to ISBN-10 from the ISBN agency. Also shows correct hyphenation & verifies if ISBNs are valid or not.
- RFC 3187 Using International Standard Book Numbers as Uniform Resource Names (URN)
- PDF (51.0 KB) for the 13-digit ISBN code.