IASA TC-04 (2009), sec. 4 Unique and Persistent Identifiers
IASA TC-04 (2009), sec. 3.2 to 3.11 External Metadata Schemes
EBU Tech 3364 (2014) Audio Definition Model: Metadata Specification
EBU Tech 3293 (2008) EBU Core
AES57-2011 (r2017) – AES Standard for audio metadata
Casey, Mike & Bruce Gordon. Sound Directions: Best Practices for Audio Preservation, Chapter 3 “Digital Files” and Chapter 4 “Metadata” . [Copyrighted] Indiana University and Harvard University, 2007.
AudioMD (Library of Congress)