663/664 Fields (New Authority Records)
Simple cross references are preferred over complex cross references, but if necessary, NACO participants use the 663 or 664.
The 663 field contains the explanatory text and the headings referred to that are required when relationships exist between an established name and other extablished names that cannot be adequately conveyed by one or more simple cross references generated from the 5XX fields. (See also LCRI 22.2B and LCRI 26.2D. ) These are often used in the case of authors using joint pseudonyms. 5XX references should contain the subfield $w with the 4th position set to c (reference not displayed, field 663 used). Subfield $b is used to list the related established headings to which the heading in field 1XX of the record refers.
The 664 field contains the explanatory text and the headings referred to that are required when relationships exist between an unestablished name and one or more established names that cannot be adequately conveyed by simple cross references generated from 4XX fields in the established heading records. 4XX references contain the subfield $w with the 4th position set to b (reference not displayed, field 664 used). Subfield $b is used to list the related established heading to which the heading in field 1XX of the record refers. 664 fields are rarely used, cf. US MARC Authority Format, 664 Complex See Also References, LC Guidelines.
See also:
Section I - New Authority Records
