1. Department of Economics, Lund University, PO Box 7082, SE-222 07 Lund, Sweden (email: )
2. Centre for Economic and Regional Studies, Institute of Economics, Toth Kalman utca 4 1097 Budapest, Hungary, and University of Potsdam, Hasso Plattner Institute (email: )
3. Département de Sciences Économiques, Université de Montréal, C.P. 6128, Montréal, Quebec H3C 3J7, Canada (email: )
4. Department of Economics, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom (email: )