3 IZA Discussion Papers
IZA Discussion Paper No. 8104
slightly revised version published in: Econometrica, 2014, 82(5), 1615-1670
IZA Discussion Paper No. 3883
published in: International Organization, 2010, 64 (1), 133-144
IZA Discussion Paper No. 1735
published in: Research in Labor Economics, 2006, 24, 35-75