1. Economics Department; University of Erlangen-Nuremberg; Lange Gasse 20 90403 Nuremberg Germany
2. Institute for the Study of Labor (IZA); Bonn Germany
3. Faculty of Business Management and Economics; University of Würzburg; Würzburg Germany
4. Centre for European Economic Research (ZEW); Mannheim Germany
5. Research Centre for Education and Labour Market (ROA); Maastricht The Netherlands