6 IZA Discussion Papers
IZA Discussion Paper No. 17295
IZA Discussion Paper No. 15886
IZA Discussion Paper No. 14171
IZA Discussion Paper No. 11167
IZA Discussion Paper No. 4941
published in: O. Ashenfelter and D. Card (eds.), Handbook of Labor Economics, Amsterdam: Elsevier, 2011
IZA Discussion Paper No. 1193
published in: American Economic Review, 2011, 101 (2), 819-843