4 IZA Discussion Papers
IZA Discussion Paper No. 16675
IZA Discussion Paper No. 7040
published in: American Economic Review, 2013, 103 (6), 2052-86
IZA Discussion Paper No. 5625
IZA Discussion Paper No. 4533
published in: Journal of Public Economics, 2010, 94 (1-2), 114-128