4 IZA Discussion Papers
IZA Discussion Paper No. 12836
IZA Discussion Paper No. 6093
published in: Applied Economics, 2013, 45 (13), 1741-1749
IZA Discussion Paper No. 1805
revised version published in: Journal of Law and Economics, 2009, 52 (3), 445-467
IZA Discussion Paper No. 1052
published in: European Economic Review, 2007, 51 (8), 1941-1958