Further Reading..
For more information about Topic Maps, here's a list of web pages that dig into the details of the Topic Maps standard :- The TAO of Topic Maps : an excellent explanation of the whole “Topic Maps” concept (http://www.ontopia.net/topicmaps/materials/tao.html)
- The ISO-13250 Topic Maps Standard : http://xml.coverpages.org/TM-iso13250-2nd-ed-v2.pdf