The following documents the changes contained in the twelfth update to the 1999 edition of MARC 21 Format for Bibliographic Data.  Update No. 12 (October 2010) includes changes resulting from proposals that were considered by the MARC 21 community during June 2010.

New content designators:

Subfield code

$u  Uniform Resource Identifier in 561 (Ownership and Custodial History)


Code c (ISBD punctuation omitted) in Leader/18 (Descriptive cataloging form)

Changes in content designator names and definitions:

Subfield code

$0  Authority record control number changed to Authority record control number or standard number and redefined in Appendix A


Code i - ISBD changed to ISBD punctuation included and redescribed in Leader/18 (Descriptive cataloging form)

See also:

Appendix G:  Format Change Lists