Agent-Mediated Electronic Commerce and Trading Agent Design and Analysis : AAMAS Workshop, AMEC 2008, Estoril, Portugal, May 12-16, 2008, and AAAI Workshop, TADA 2008, Chicago, IL, USA, July 14, 208, Revised, Selected Papers - Wolfgang Ketter, Han Poutré, Norman Sadeh, Onn Shehory, William Walsh ((Lecture Notes in Business Information Processing))