When it is known there are separate ISSN assigned to different formats of a series represented by a single SAR, prefer to record in 022 subfield $a the ISSN that is the linking ISSN (ISSN-L) for the different formats. Identify ISSN for specific formats in separate 667 fields, following this pattern: | When it is known there are separate ISSN assigned to different formats of a series represented by a single SAR, prefer to record in 022 subfield $a the ISSN that is the linking ISSN (ISSN-L) for the different formats. Identify ISSN for specific formats in separate 667 fields, following this pattern: |