The Library of Congress is postponing implementation of the 781 field in name authority records for geographic headings that may also be used as geographic subdivisions until the Voyager system implements the indexing of MARC 21 value "f" in the 008/09 in name and subject authority records. Currently, appropriate subject authority records have the 781 field added, and those records that need the value "f" once its usage has been implemented have been marked for future correction.
PCC catalogers have been given the option of including the 781 field in name authority records. LC catalogers are asked not to change the 781 data in those NARs when making other changes to a record. If a change needs to be made to the 151 field, LC catalogers are asked to consult with CPSO.
Guidelines for the use of the 781 field by PCC catalogers are given in the following specific sections of supplements to the MARC 21 Authority Format: 781 "blue" page, 781 "yellow" page, and an excerpt from the 667 "yellow" page.