| COMARC/B | June | 2006 |
This field contains an International Standard Book Number (ISBN) and a qualification which distinguishes between ISBN when more than one is contained in a record. The field corresponds to the ISBD Standard Number (or Alternative) and Terms of Availability Area. The field may contain the terms of availability and/or price, even if it does not contain an ISBN (see example 3).
A correctly applied ISBN including hyphens. The ISBN is assigned by the designated agency in each country.
An identification of the scope of the ISBN in subfield a (if present): usually the name of a publisher, an indication of the binding of the item, or an indication of the relationship of an ISBN to a set or to a particular volume (see examples 3, 5, 6, 7, 11, 12, 14). Within the COBISS software a qualification is entered without brackets because they are displayed automatically.
An ISBN that has been identified as being erroneously applied to an item or is otherwise invalid. It may have been allocated to two different publications and in this instance cancelled (see example 8), or it may have been incorrectly printed (see example 9). If the National ISBN Agency locates an erroneous ISBN entered in the subfield a, it sends a message on that matter to the library that transports data in subfield z.
The ISBN is a unique number applied to a published item according to the provisions of ISO 2108.
ISBN-10 consists of four parts that are separated by a hyphen or space. Those parts are:
Group identifier: Allocated to each country or group of countries or language groups by the International ISBN Agency. International organizations e.g., the UN also have their own group identifier.
Publisher identifier: Allocated to each publisher by a National or Regional ISBN Agency.
Title identifier: Allocated to each title (and each edition and format of each title) by the publisher
Check digit: calculated on the basis of the other nine digits of the ISBN.
ISBN-10 consists of numeric digits except the check digit which may be numeric or a roman numeral X.
ISBN-13 consists of five parts; to 10-characters ISBN a three-digit number is added and the check number which is calculated anew:
Prefix element: A three-digit number that is made available by EAN, which designates the book industry (978, 979).
Check digit: it is calculated on the basis of the other twelve ISBN digits.
Together with a check digit, ISBN-13 consists of numeric digits from 0 to 9.
To check for accuracy of an ISBN: take each digit and multiply by a number whose value depends on the position of the digit (the "weight"), add the results and divide by 11. If the answer is not zero then one or more of the digits is wrong. Using example 9 as an example:
| ISBN | 0 | 1 | 1 | 8 | 8 | 4 | 0 | 9 | 4 | X (i.e. 10) |
| "Weight" | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
| Result | 0 | 9 | 8 | 56 | 48 | 20 | 0 | 27 | 8 | 10 = total 186 |
186 is not exactly divisible by 11, so the ISBN is incorrect.
The check digit is calculated using a modulus 10 algorithm.
Each of the first 12 digits of the ISBN – except the check digit – is alternately multiplied by 1 and 3 from left to right. The sum of the weighted products of the first 12 digits plus the check digit must be divisible by 10 without a remainder for the ISBN to be valid.
Example:
| Prefix element | Registr. group el. | Registrant element | Publication element | Check digit | Sum | |||||||||
| ISBN | 9 | 7 | 8 | 0 | 3 | 9 | 3 | 0 | 4 | 0 | 0 | 2 | 9 | |
| "Weight" | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 | - | |
| Product | 9 | 21 | 8 | 0 | 3 | 27 | 3 | 0 | 4 | 0 | 0 | 6 | - | 81+9 |
Total: 81 + 9 (check digit) = 90
90 is exactly divisible by 10, so the ISBN 978-0-393040-02-9 is correct international standard book number.
The letters ISBN, which are usually found printed with an ISBN on the item, should not be entered in field 010.
Any ISBN which is found to be wrongly printed on the item can be entered in subfield 010z – Erroneous ISBN. This is provided to enable search by an erroneous number appearing on the item.
Hyphens are inserted to separate the four (ISBN-10) or five (ISBN-13) separate parts of the ISBN in subfields a and z. No other punctuation is permitted. When ISBN is displayed in a catalogue entry the inclusion of the hyphens or spaces is mandatory. Many national agencies do not store hyphens or spaces in the machine-readable record since they can be generated by algorithm if the range of publisher identifiers which have been allocated is known. When records are exchanged internationally the recipient of records may not always know the range of publisher identifiers allocated within the group represented by the first part of the ISBN. Therefore it is recommended that hyphens always be included in the ISBN in field 010 to ensure their display on output.
Strictly, each book has one ISBN. However, there are circumstances in which a single record may need to include more than one ISBN, namely: when a publisher issues a work in more than one binding or physical format, each with a different ISBN, and a single record is created by the agency encompassing more than one of these "editions"; when a single record is created for a multipart item (multi-volume monograph) and different ISBN have been assigned by the publisher to each volume and to the set as a whole; when a single item is published, or published and distributed, by more than one entity, each of which has assigned a separate ISBN to the item.
In order to distinguish between ISBN when there is more than one in a record, qualifications may be added to one or more of them.
Terms of availability and price are often related to each ISBN. Thus this information is recorded in the same field.
The field should be repeated for each valid ISBN. It should also be repeated for an invalid ISBN unless that invalid ISBN clearly relates to a known valid equivalent entered in the record, in which case the invalid ISBN will be entered in the same field as its corresponding valid ISBN (see examples 8, 9).
| 011 | ISSN |
| A number similar in use to the ISBN but applied to continuing resources. |
010 ⊔⊔ a0-246-11007-4 d£2.95 (A book published in England and cloth bound priced at £2,95 with the ISBN on the document as follows: 0 246 11007 4.) 010 ⊔⊔ a963-592-149-7 d$25.00 (outside Hungary) (A book published in Hungary and sold outside the country for $25,00.) 010 ⊔⊔ d£3.50 010 ⊔⊔ bpbk d£2.50 (A book published in both cloth and paper covers. No ISBN is available.) 010 ⊔⊔ a0-85997-276-3 d£5.20 (£3.90 to members of the Library Association) (A book is published with a discount to members of the Library Association.) 010 ⊔⊔ a0-915408-15-5 dUnpriced 010 ⊔⊔ a0-915408-16-3 bSigned ed. dUnpriced (A book is available in cloth bound form with the option of purchasing it in a cased edition signed by the translator. The alternatives each have their own ISBN.) 010 ⊔⊔ a0-306-35054-8 d£22.05 010 ⊔⊔ a0-306-35050-5 bSet of six vols d£97.29 (The record for volume 4 of a monograph "Treatise on solid state chemistry" published in 6 volumes, each with its own ISBN. The set also has an ISBN and a price is available for the set.) 010 ⊔⊔ a0-563-12887-9 b(B.B.C.) 010 ⊔⊔ a0-233-96847-4 b(Deutsch) (A book is jointly published by the British Broadcasting Corporation and Deutsch.) 010 ⊔⊔ a0-11-884094-0 z0-11-884094-X (ISBN 0-11-884094-0 is incorrectly printed with an X as the check digit.) *
010 ⊔⊔ a86-11-02519-9 200 0⊔ aPodobe iz življenja in sanj *
010 ⊔⊔ a86-7217-081-4 bzv. 1 010 ⊔⊔ a961-6238-22-1 bzv. 2 200 0⊔ aPreoblikovanje *
010 ⊔⊔ a86-81171-01-1 bbroš. 200 1⊔ aSplošni tehnični pogoji *
010 ⊔⊔ a0-393040-02-X 010 ⊔⊔ a978-0-393040-02-9 (The check digits of the 10- and 13-characters ISBN are different.) *
010 ⊔⊔ a978-951-45-9693-3 010 ⊔⊔ a978-951-45-9694-0 bbroš. 010 ⊔⊔ a978-951-45-9695-7 bPDF 010 ⊔⊔ a978-951-45-9696-4 bHTML (A book is published in both cloth and paper covers. It is also published in electronic form (PDF and HTML). From January, 1 2007 to all new publications a 13-character ISBN will be assigned.)