020 International Standard Book Number

Field definition and scope:

Field 020 contains the International Standard Book Number (ISBN), the terms of availability, and any canceled or invalid ISBN copied from field 020 of a MARC bibliographic record for a multipart item that is cataloged as a set.

The inclusion of this field in the established heading record for a series provides a machine link within a system between the authority record for the series and a bibliographic record in which the heading is used as a series added entry. Each valid ISBN associated with the series is contained in a separate 020 field. The subfields in this field are defined for consistency with field 020 in MARC 21 Format for Bibliographic Data.

An International Standard Serial Number (ISSN) associated with a heading for an issue of a serial for which series-type treatment is provided is contained in field 022 (International Standard Serial Number).

The National level record requirement for this field is Mandatory if applicable.

Field 020 is repeatable.

Guidelines for applying content designators:

For indicator and subfield code definitions and examples, National level (NLR) record requirements, and designator repeatability, see table below:

Position	Description	NLR	Repeatability
Field 020	International Standard Book Number	A	R
Indicator:
First	Undefined; contains a blank	M
Second	Undefined; contains a blank	M

Subfield code:
$a	International Standard Book Number	A	NR
$c	Terms of availability	O	NR
$q	Qualifying information		R
$z	Canceled or invalid ISBN	A	R
$6	Linkage	A	NR
$8	Field link and sequence number	O	R

Input conventions:

ISBN structure

Display constants

Content designator history:

Subfield $q - Qualifying information [new, 2013]

Prior to the definition of subfield $q in 2013, qualifying information was contained in subfield $a (International Standard Book Number) and $z (Canceled/invalid ISBN).

LC Guidelines:

020 International Standard Book Number