1. Faculty of Commerce, University of British Columbia, 2053 Main Mall, Vancouver, BC, V6T 1Z2 Canada.
2. Department of Economics, University of British Columbia, 997-1873 East Mall, Vancouver, BC, V6T 1Z1 Canada.
3. Department of Economics, Social Science Building 6448, University of Wisconsin, 1180 Observatory Drive, Madison, WI 53706.