5 IZA Discussion Papers
IZA Discussion Paper No. 17361
IZA Discussion Paper No. 10095
IZA Discussion Paper No. 7064
IZA Discussion Paper No. 2845
published in: Fiscal Studies, 2007, 28 (4), 463-495
IZA Discussion Paper No. 1383
published in: Empirica, 2005, 32 (3-4), 309-343