Group Communications and Charges; Technology and Business Models 5th COST264 International Workshop on Networked Group Communications, NGC 2003, and 3rd International Workshop on Internet Charging and QoS Technologies, ICQT 2003, Munich, Germany, September 16-19, 2003 Proceedings - Stiller, Burkhard; Stiller, Burkhard; Carle, Georg; Carle, Georg; Karsten, Martin; Karsten, Martin; Reichl, Peter; Reichl, Peter (Springer Berlin Heidelberg : Imprint: Springer, 2003)