The following documents the changes contained in the twenty-eighth update to the 1999 edition of MARC 21 Format for Authority Data.  Update No. 28 (May 2019) includes changes resulting from proposals that were considered by the MARC 21 community since the publication of Update No. 27 (November 2018).

New content designators:

Subfield codes

$0  Authority record control number or standard number (NR) in 024 (Other Standard Identifier)

$1  Real World Object URI (NR) in 024 (Other Standard Identifier)

Change in content designator name and definition:

Subfield code

$2  Source of number or code renamed Source in 024 (Other Standard Identifier).

See also:

Appendix F:  Format Change Lists