Appendix A contains descriptions of three subfields that are used to link field data to other fields.  These subfields are defined for most fields in the format, thus their descriptions are brought together in this appendix.  The subfields are included in field level subfield lists wherever they are defined, with links to this appendix.

Specific subfield information:

$0  Authority record control number or standard number

$6  Linkage

$8  Field link and sequence number

Content designator history:

$0Authority record control number  [new, 2007]

$0Authority record control number  [redefined, 2010]

$0Authority record control number or standard number  [redescribed, 2016]

In 2016, the requirement to precede a dereferenceable URI (such as an HTTP URI) in subfield $0 with the parenthetical prefix code "(uri)" was removed.

$8 - Field link and sequence number

p - Metadata provenance  [new, 2012]

u - General linking, type unspecified  [new, 2016]

See also:

Appendices