s of April 2001, NLM's bibliographic control number(s) will appear in the OCLC Worldcat in the 016 - National Bibliographic Agency Control Number field rather than in the 069 - Other System Control Number field previously used for this purpose. This change is the result of OCLC's implementation of the MARC 21 field 016 as defined in MARC 21 Format for Bibliographic Data, published by the Library of Congress. This change is of particular importance to catalogers and other users of NLM records on OCLC accustomed to locating the NLM bibliographic control number in the 069 field. This change does not affect the location of the NLM control numbers in records in LocatorPlus or the location of control numbers in NLM bibliographic products distributed to licensees.

OCLC plans to move existing NLM control numbers in field 069 to field 016 on or about April 1, 2001. If the record in OCLC contains multiple 069 fields, all occurrences of the 069 field will be moved to multiple occurrences of the 016 field.

Valid NLM control numbers will be moved to the 016 subfield a. Cancelled or invalid NLM control numbers will be retained by OCLC in the 016 subfield z. All NLM control numbers will be identified by the source value "DNLM" in the 016 subfield 2.

Shown below is a portion of OCLC Record Number 35331394, an NLM record with one 069 field.

Shown below is a portion of OCLC Record Number 41946557, an NLM record with two 069 fields.

For information on the format of the 016 field, see the MARC 21 Format for Bibliographic Data document available at http://www.loc.gov/marc/bibliographic/ecbdhome.html. For additional information on OCLC's implementation of field 016, refer to "OCLC Technical Bulletin 241: National Library Control Number Changes" at http://www.oclc.org/oclc/tb/tb241 [Editor's Note: This link was removed because it is no longer valid.].

For information on searching the OCLC 016, please refer to "OCLC Technical Bulletin 235 Rev.: Keyword Searching Changes in WorldCat" available at http://www.oclc.org/oclc/tb/tb241. Both subfields a and z are searchable by keyword.

Marti Scheel
Cataloging Section

Scheel M. National Library of Medicine Bibliographic Control Numbers in OCLC WorldCat. NLM Tech Bull. 2001 Mar-Apr;(319):e5.