Snijder, Ronald: Metadata standards and information analysis: a survey of current metadata standards and the underlying models. Electronic resource, available at http://www.geocities.com/ronaldsnijder/

Sollins, Karen & Masinter, Larry: Functional requirements for Uniform resource names. RFC 1737. Electronic resource, available at http://www.ietf.org/rfc/rfc1737.txt

Tillett, Barbara: Bibliographic relationships. In: C. A. Bean & R. Green: Relationships in the Organization of Knowledge, 19-35. 2001.