DCM Z1:  010  Library of Congress Control Number

LC series practice:  As of June 1, 2006, LC does not create or update SARs.

PCC series practice:  Transcription of the series statement is mandatory if applicable.  Searching for series authority records, tracing the series, and the creation and maintenance of series authority records are optional.

When one authority record is being deleted in favor of another authority record, give the LCCN of the deleted record in subfield $z of the 010 field in the retained record.  This action may result in a mixture of old and new-structure LCCNs.  When inputting the LCCN, follow the conventions appropriate to the structure of that LCCN.  Do not convert old-structure LCCNs to new-structure LCCNs, or vice versa.  (See DCM C3 for additional information.)


[blank space = system-supplied space for clarity in display; "#" = space input by cataloger]

010  ##  $a n##99001234# $z no#99222222# $z n##99500045#

[All LCCNs are old-structure.]

010  ##  $a nr2001040302 $z n#2001000888

[All LCCNs are new-structure.]

010  ##  $a n##99123456# $z n#2001123456

[LCCN in subfield $a is old-structure; LCCN in subfield $z is new-structure.]

010  ##  $a no2001333333 $z nb#99000123#

[LCCN in subfield $a is new-structure; LCCN in subfield $z is old-structure.]

Do not "re-use" an LCCN.  Once an authority record for a specific entity is created and an LCCN is assigned to the record, do not change the data in that record to represent a DIFFERENT entity.  For example, do not change an NAR for "Smith, John" to "Jones, Mary" (unless the person's name has changed).

When a duplicate authority record is identified, delete the record.  Do NOT "fix up" the record by deleting the 040 $d in the record and keying in all new fixed and variable fields so that the record "looks" new.  This action causes problems for LC, CDS, the bibliographic utilities, and other libraries' systems.


[010 Guidelines for Library of Congress Staff for Generation of Library of Congress Control Numbers (LCCNs) for name authority records is excluded from this topic.]

For more information on DCM Z1 Instructions, select:

DCM Z1:  Introduction