The purpose of the following document is to provide guidelines for handling ISBN information for copy cataloging purposes, particularly when you find multiple ISBNs on the title being cataloged.
1) Adding new 020 fields to copy records
When the hardcover and paperback versions were published simultaneously, their ISBNs should be recorded in the same record (in subfield $a) as long as the only difference concerns types of binding. [An ISBN for a different format, including the large print version with different pagination and/or dimensions, will be recorded as an invalid ISBN; see below).
020 $a 0198702337 ǂq (hbk.)
020 $a 0198702345 ǂq (pbk.) [ISBN for the paperback version published in the same year; add if this ISBN is found on the title being cataloged but is missing in the existing record]
Another typical situation is when you are cataloging a new volume in a multi-volume set and the existing record in OCLC or Alma lacks an ISBN for the added volume.
020 $a 9780415364232 ǂq (v. 1 ; ǂq alk. paper)
020 $a 9780415364249 ǂq (v. 2 ; ǂq alk. paper) [add the 2nd volume ISBN to a multi-volume record]
When adding ISBNs, generally follow the parenthesis patterns used in the existing record. The examples below are both acceptable.
020 $a 9780415364232ǂq (hbk.)
020 $a 9780415364249ǂq (pbk.)
020 $a 9780415364232ǂq hbk.
020 $a 9780415364249ǂq pbk.
2) Recording invalid ISBNs for other formats
When multiple ISBNs for print and ebook versions are found on the title being cataloged, either of them are obviously invalid ISBNs for the version at hand. Make sure that all invalid ISBNs found are added in subfield $z if they are missing in the bibliographic records. Not doing so could have negative implications for users (because they might use those ISBNs for searching) or for the acquisitions workflow (e.g., checking for existing library copies). Record first the ISBN that is applicable to the title being cataloged, followed by the other invalid ISBNs in the order presented, with appropriate qualification to distinguish.
020 $a 9780702054389 $q (electronic bk.)
020 $a 0702054380 $q (electronic bk.)
020 $z 9780702053351 $q (paperback)
020 $a 9780702053351$q (paperback)
020 $a 070205335X $q (paperback)
020 $z 9780702054389 $q (PDF)
020 $z 9780702054389 $q (ePUB)
For print versions, if the title being cataloged represents a difference resource from the other version(s) (e.g., paperback published in a later year), record "invalid" ISBNs for the other version(s) if found on the title at hand and missing in the existing record. Information like "First issued in paperback in ...." or "First paperback edition" found on title page verso often provides clear evidence that ISBNs for the other version(s) should be recorded as invalid ISBNs in subfield $z. In cases of doublt, however, record all ISBNs found in subfield $a.
When adding ISBNs, generally follow the parenthesis patterns used in the existing record. In other words, parentheses should be added when the existing ISBNs on copy records are recorded using parentheses in subfield $q, while no parentheses should be added when existing information in subfield $q is recorded with no parentheses.
020 $a 9780415364232ǂq (hbk.)
020 $z 9780415364249ǂq (pbk.)
020 $z 9780415364949ǂq (ebook)
020 $a 9780415364232ǂq hbk.
020 $z 9780415364249ǂq pbk.
020 $z 9780415364949ǂq ebook
2) Accepting existing 020 fields on copy records
For copy cataloging purposes, existing 020 fields should be accepted in copy records even when they are formatted without subfield $q or ISBD punctuation). The following examples are all acceptable for existing 020 fields in copy records:
020 $a 9780415364232 (v. 1 ; ǂq alk. paper)
020 $a 9780415364232 ǂq (v. 1 ; ǂq alk. paper)
020 $a 9780415364232 ǂq v. 1 ǂq alk. paper [formatted according to LC MARC documentation]
Note: Remember to correct incorrect ISBD punctuation found on copy records
020 $a 9780415364232 ǂq (v. 1 : ǂq alk. paper)
Change to
020 $a 9780415364232 ǂq (v. 1 ; ǂq alk. paper) [The incorrect colon above is changed to a semi-colon according to the ISBD puncutation rule.]
YT 2018-10, 2019-10, 2023-09, 2024-05, 2024-06, 2024-10