5 IZA Discussion Papers
IZA Discussion Paper No. 2279
published in: Oxford Bulletin of Economics and Statistics, 2010, 72 (6), 717-743
IZA Discussion Paper No. 2112
published in: Stata Journal, 2006, 6 (2), 156-189
IZA Discussion Paper No. 1251
revised version published in: Labour Economics, 2010, 17 (1), 150-169
IZA Discussion Paper No. 729
IZA Discussion Paper No. 676