<hi xmlns="http://www.tei-c.org/ns/1.0" rend="bold">W3C</hi>: SKOS Simple Knowledge Organization System Reference. W3C Recommendation 18 August 2009 <ref xmlns="http://www.tei-c.org/ns/1.0" target="https://www.w3.org/TR/2009/REC-skos-reference-20090818/">https://www.w3.org/TR/2009/REC-skos-reference-20090818/</ref>) [letzter Zugriff: 22.09.2017]