Agent-Mediated Electronic Commerce. Designing Trading Strategies and Mechanisms for Electronic Markets : AAMAS Workshop, AMEC 2009, Budapest, Hungary, May 12, 2009, and IJCAI Workshop, TADA 2009, Pasadena, CA, USA, July 13, 2009, Selected and Revised Papers - Esther David, Enrico Gerding, David Sarne, Onn Shehory ((Lecture Notes in Business Information Processing))