Authorities notes are indexed by Zebra for UNIMARC records, but not for MARC21. We could index them in "note" index like for UNIMARC : 667 Nonpublic General Note (R) 670 Source Data Found (R) 672 Title Related to the Entity (R) 673 Title Not Related to the Entity (R) 675 Source Data Not Found (NR) 678 Biographical or Historical Data (R) 680 Public General Note (R) 681 Subject Example Tracing Note (R) 682 Deleted Heading Information (NR) 688 Application History Note (R) M. Saby