|Mandatory||Repeatable||Data Type||Authority||Public Element|
|Yes||Yes||Variable Character Length (2000)||Geographic Source Authority||Yes|
Resources cited to develop and support headings and references in an authority record.
Documents sources consulted to develop and document the form of headings and references in an authority record.
See the Subject Cataloging Manual: Subject Headings (Library of Congress) and MARC21Format for Authority Data online.