- Proc. of E-Learning 2002 World Conference on E-Learning in Corporate, Government, Healthcare and Higher Education on E-Learning 2002, AACE, page 909-915. Norfolk, (2002)Awarded paper .
- page 273-290. Springer, (2006)
- Mobiles Lernen und Forschen - Beiträge der Fachtagung an der Universität, page 93-104. Kassel University Press, (November 2003)
- Proc. 13th International World Wide Web Conference WWW 2004, page 1-10. (2004)
- Springer, Heidelberg, (2006)
- Heraklion, Greece, (May 2005)
- Proc. ESWC 2005 Workshop on Ontologies in Peer-to-Peer Communities, Heraklion, Greece, (May 2005)
- Proc. International Conference on Knowledge Management I-Know 2004, Graz, Austria, (June 2004)


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