1. Exchangeable Faceted Metadata Language, XFML (2003),
http://www.xfml.org/
2. XML Topic Maps (XTM) (2001),
http://www.topicmaps.org
3. World Wide Web Consortium site (W3C),
http://www.w3c.org
4. XML Path Language (XPath). World Wide Web Consortium site, W3C (2003-2005),
http://www.w3c.org/TR/xpath20/
5. XML Query (XQuery). World Wide Web Consortium site (W3C), The Architecture Domain (2003-2005),
http://www.w3.org/XML/Query