What MARC formats are supported in Koha for Authority Control?

Koha supports both MARC21 and UNIMARC standards for Authority Control.

One feature of UNIMARC that is especially attractive is the storage of a link ID at the bibliographic tag level in $6 that maintains it easy to point to the appropriate

001 tag of the appropriate Authority record -- this makes it very simple to reference and update bibliographic data when authority data is changed. The MARC21 standards committee will be adding this feature into the MARC21 standard for authorities shortly as a $0, but you can begin using Koha authority records with identifiers linking bibliographic and authority data immediately using the local-use $9 (set up by default in new Koha installations).