1. Department of Economics, University of St. Gallen, Bodanstrasse 8, 9000 St. Gallen, Switzerland (e-mail: )
2. Department of Economics, University of Lucerne, Frohburgstrasse 3, 6002 Lucerne, Switzerland (e-mail: )
3. Faculty of Business and Economics, University of Basel, Peter Merian-Weg 6, 4002 Basel, Switzerland (e-mail: ).