Antonio Gómez Tato, Universidade de Santiago de Compostela (Spain), July 25-26, 2006

Daniel Tanré, Université de Lille 1 (France), July 11-20, 2006

Gustavo Granja, Instituto Superior Técnico, March 20-21 and June 5-15, 2006

Hans Scheerer, Freie Universität Berlin (Germany), October 3-9, 2006

John Harper, University of Rochester (USA), June 2-22, 2006

Joseph Neisendorfer, University of Rochester (USA), October 13-30, 2006