TECHNICAL NOTICE (June 1, 2022) Additions to Source Codes for Vocabularies, Rules, and Schemes Network Development and MARC Standards Office Library of Congress ________________________________ The source codes listed below have been recently approved. The codes will be added to the applicable Source Codes for Vocabularies, Rules, and Schemes<https://www.loc.gov/standards/sourcelist/> lists. See the specific source code lists for current usage in MARC fields and MODS/MADS elements. The codes should not be used in exchange records until 60 days after the date of this notice to provide implementers time to include newly-defined codes in any validation tables. Subject Heading and Term Source Codes The following source codes have been added to the Subject Heading and Term Source Codes<https://www.loc.gov/standards/sourcelist/subject.html> list for usage in appropriate fields and elements. * Additions: * qlit - Queer literature indexing thesaurus (Göteborg: Göteborgs universitetsbibliotek, KvinnSam) * tef - Tesauro especializado en filosofía, con enfoque de género by Marcia Ugarte Barquero The Library of Congress, Network Development and MARC Standards Office provides information about existing and newly assigned MARC codes on its Web site (www.loc.gov/marc/<https://www.loc.gov/marc/>) as well as notices such as these to subscribers to its MARC listserv.