Master Reference File

The Master Reference File (MRF) is an electronic form of the UDC schedules held in a database. It contains the definitive, authorized version of the UDC and is maintained as a working tool for the UDC Consortium. Proposals for change are published annually in "Extensions and corrections," and all agreed cancellations are published on the UDCC web site.

The Consortium created and maintains the MRF database in order to manage the content of the UDC, to determine the need and priority for revisions, and to keep track of changes over time. The database is updated annually. The MRF is the definitive source on which publishers base their UDC publications or services.