E-Commerce and Web Technologies 5th International Conference, EC-Web 2004, Zaragoza, Spain, August 31-September 3, 2004, Proceedings - Bauknecht, Kurt; Bauknecht, Kurt; Bichler, Martin; Bichler, Martin; Pröll, Birgit; Pröll, Birgit (Springer Berlin Heidelberg : Imprint: Springer, 2004)