1. Institute of Applied Economics, HEC Montreal, 3000, chemin de la Cte-Sainte-Catherine, Montréal, Québec, Canada, H3T 2A7 (e-mail: )
2. Dipartimento di Scienze Economiche, Universitá di Bologna, Piazza Scaravilli 2, 40126 Bologna, Italy, and Department of Economics European University Institute, via Piazzola 43, 50133 Firenze, Italy (e-mail: )
3. Kellogg School of Management, Northwestern University, 2001 Sheridan Road Evanston, IL 60208 (e-mail: )