4 IZA Discussion Papers
IZA Discussion Paper No. 17053
IZA Discussion Paper No. 6634
published in: Journal of Public Economics, 2012, 96 (9-10), 712-726
IZA Discussion Paper No. 5291
IZA Discussion Paper No. 2843
published in: American Economic Review, 2011, 101 (4), 1274-1311