1. Department of Economics; University of California; Irvine CA 92697 USA
2. Compass Lexecon; 200 State Street 9th Floor Boston MA 02109
3. Department of Economics; University of Luxembourg; Campus Limpertsberg 162 A avenue de la Faïencerie L-1511 Luxembourg
4. Department of Economics; University of Minnesota; 1925 4th St S Room 4-101 Minneapolis MN 55455