J. Tane, C. Schmitz, G. Stumme, S. Staab, and R. Studer. Mobiles Lernen und Forschen - Beiträge der Fachtagung an der Universität, page 93-104. Kassel University Press, (November 2003)
B. Omelayenko. Proceedings of the International Workshop on Web Dynamics, held in conj. with the 8th International Conference on Database Theory (ICDT’01), London, UK, (2001)
J. Gemmell, G. Bell, R. Lueder, S. Drucker, and C. Wong. Proceedings of the tenth ACM international conference on Multimedia (MM-02), page 235--238. New York, ACM Press, (December 2002)