1. Department of Economics, School of Business and Economics, Maastricht University, PO Box 616, NL-6200MD Maastricht, the Netherlands.
2. Utrecht University School of Economics (USE), Utrecht University, PO Box 80125, NL-3508TC Utrecht, the Netherlands
3. Department of Management, Economics and Quantitative Methods, University of Bergamo, Via dei Caniana, 2, I-24127 Bergamo, Italy