First Author:   Gil S. Epstein Bar-Ilan University epsteig@mail.biu.ac.il   Department of Economics, Bar-Ilan University, Ramat Gan 52900, Israel Ramat Gan, 52900, Israel   972 52 8550407(Phone) 972 52 8550407(Fax) http://faculty.biu.ac.il/~epsteig/ Second Author: Shmuel Nitzan Bar-Ilan University nitzans@mail.biu.ac.il   Department of Economics, Bar-Ilan University, Ramat Gan 52900, Israel Ramat Gan, 52900, Israel