1. Alistair Miles, Sean Bechhofer, SKOS simple knowledge organization system reference, W3C Recommendation, World Wide Web Consortium, 18 August 2009. URL: http://www.w3.org/TR/skos-reference/.
2. Alistair Miles, Nikki Rogers, Dave Beckett, SKOS-Core 1.0 guide, Technical Report, World Wide Web Consortium, 4 May 2004. URL: http://www.w3.org/2001/sw/Europe/reports/thes/1.0/guide/20040504/.
3. Antoine Isaac, Jon Phipps, Daniel Rubin, SKOS use cases and requirements, W3C Working Group Note, World Wide Web Consortium, 18 August 2009. URL: http://www.w3.org/TR/skos-ucr/.
4. ISO TC46/SC9. ISO 2788:1986 documentation—guidelines for the establishment and development of monolingual thesauri, Technical Report, International Organization for Standardization, 1986.
5. ISO TC46/SC9/WG8 working group for the ISO 25964 standard about Thesauri, ISO 25964-1:2011 Information and documentation–Thesauri and interoperability with other vocabularies—part 1: thesauri for information retrieval, Technical Report, International Organization for Standardization, 2011.