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020 International Standard Book Number (R)

Find the field definition and scope, indicators, subfield codes, and guidelines for applying content designations for field 020.

Indicators and subfield codes

First Indicator


blank          Undefined

Second Indicator


blank          Undefined

Subfield Codes

‡a        International Standard Book Number (NR)

‡c        Terms of availability (R)

‡q        Qualifying information (R)

‡z        Canceled/invalid ISBN (R)

‡8        Field link and sequence number (R)


Field definition and scope

This field contains the International Standard Book Number (ISBN) copied from subfield ‡a of field 020 (International Standard Book Number) of the MARC bibliographic record that represents the description of the item for which a separate holdings record is created. It may also contain terms of availability and any canceled or invalid ISBN from subfields ‡c and ‡z of field 020 in the bibliographic record. If the bibliographic record contains multiple valid ISBNs that refer to different versions of the item, the one that corresponds to the item described in the holdings statement is used.

Additional information and description of the use of field 020 (International Standard Book Number) is in OCLC Bibliographic Formats and Standards.

An ISBN is a unique number assigned to an item by its publisher. Each ISBN is a ten- or thirteen-digit number and has four parts: the language group of the country of publication, the publisher, the title, and the check character.

Thirteen-digit ISBNs must begin with either 978 or 979 (a 13-digit EAN beginning with 978 or 979 may be input as a valid ISBN).

If printed in a book, catalog or bibliography, these four parts are usually separated by hyphens. Do not enter the hyphens. If the final character is an x, enter an uppercase X.

Guidelines for applying content designations


Both indicators are undefined; each contains a blank (blank).

First Indicator - Undefined

blank - Undefined

Second Indicator - Undefined

blank - Undefined


‡a - International Standard Book Number

Subfield ‡a contains a valid ISBN for the item. Parenthetical qualifying information, such as the publisher/distributor, binding/format, and volume numbers, is not separately subfield coded.

020          0456789012 (reel 1)

‡c - Terms of availability

Subfield ‡c contains the price or a brief statement of availability and any parenthetical qualifying information about availability.

020          ‡z 0877790105 (Fabrikoid) : ‡c $12.00

‡q - Qualifying information

Subfield ‡q contains a brief statement of qualifying information concerning the item associated with a number being recorded in subfield ‡a or subfield ‡z.

020          0893571121 ‡q (pbk. ; ‡q v. 1)

‡z - Canceled/invalid ISBN

Subfield ‡z contains a canceled or invalid ISBN and any parenthetical qualifying information.

Each canceled/invalid ISBN is contained in a separate subfield ‡z. If no valid ISBN exists, subfield ‡z may be used alone in the record.

020          0877790019 (black leather) ‡z 0877780116 : ‡c $14.00

‡8 - Field link and sequence number

Subfield ‡8 contains data that identifies linked fields and may also propose a sequence for the linked fields. Subfield ‡8 may be repeated to link a field to more than one other group of fields.

The structure and syntax for the field link and sequence number subfield is: ‡8<linking number>.<sequence number>

The linking number is the first data element in the subfield and required if the subfield is used. It is a variable-length whole number that occurs in subfield ‡8 in all fields that are to be linked. Fields with the same linking number are considered linked. A linking number of "0" (zero) is not used in this field.

The sequence number is separated from the linking number by a period "." and may be optional. It is a variable-length whole number that may be used to indicate the relative order for display of the linked fields (lower sequence numbers displaying before higher ones).

Subfield ‡8 is always the first subfield in the field when it is used.