1. Department of Economics, Florida State University, Tallahassee, Florida 32306;
2. School of Economics, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom;
3. Department of Economics, University of North Carolina at Charlotte, Charlotte, North Carolina 28223;
4. George Herbert Walker School of Business and Technology, Webster University Geneva, Bellevue, 1293 Switzerland;
5. GATE, F-69130 Ecully, France;
6. Univ Lyon, CNRS, GATE UMR 5824, F-69130 Ecully, France;
7. IZA – Institute of Labor Economics, D-53113 Bonn, Germany