Subfield $0 contains the system control number of the related authority or classification record, or a standard identifier such as an International Standard Name Identifier (ISNI).  These identifiers may be in the form of text or a URI.  If the identifier is text, the control number or identifier is preceded by the appropriate MARC Organization code (for a related authority record) or the Standard Identifier source code (for a standard identifier scheme), enclosed in parentheses.  When the identifier is given in the form of a Web retrieval protocol, e.g., HTTP URI, no preceding parenthetical is used.

See MARC Code List for Organizations for a listing of organization codes and Standard Identifier Source Codes for code systems for standard identifiers.  Subfield $0 is repeatable for different control numbers or identifiers.

Subfield $0 is to be used for recording URIs which represent objects in RDF triple statements.

Note:  Subfield $0 may be referred to in the field descriptions as Record control number.

Examples:

710  20  $aRoyal Society of Medicine Services (Great Britain)$0(DLC)n##86108151#

511  20  $aCongrès européen de droit rural$0(DLC)n##82111965#

730  #0  $aDead Sea scrolls$0(DLC)n##79071139#

751  #0  $aZimbabwe$0(DLC)n##80089993#

024  7#  $a8462832856536435$2isni

[ISNI for Ruth Rendell]

100  1#  $aRendell, Ruth,$d1930-

500  1#  $aVine, Barbara,$d1930$0(isni)1422458635730476

[ISNI for Barbara Vine]

670  ##  $aHer From Doon with death, 1964.

670  ##  $aHer A dark-adapted eye, 1986:$bCIP t.p. (Barbara Vine)

670  ##  $aInfo. from pub., 1/28/86$b(Barbara Vine is pseud. used by Ruth Rendell)

380  ##  $aDiaries$2lcgft$0http://id.loc.gov/authorities/genreForms/gf2014026085

To return:

Use the key.

See also:

Appendix A:  Control Subfields