4 IZA Discussion Papers
IZA Discussion Paper No. 1935
IZA Discussion Paper No. 1586
published in: Industrial and Labor Relations Review, 2008, 61 (3), 374 - 393
IZA Discussion Paper No. 1521
published in: Review of Economic Studies, 2010, 77 (3), 972-1001
IZA Discussion Paper No. 935
published in: Labour Economics, 2004, 11 (6), 741-763