7 IZA Discussion Papers
IZA Discussion Paper No. 8971
published in: Journal of the European Economic Association, 2018, 16 (1), 232–274
IZA Discussion Paper No. 8404
IZA Discussion Paper No. 7217
published in: German Review of Social Policy, 2013, 62 (5), 131-139
IZA Discussion Paper No. 6056
IZA Discussion Paper No. 5325
improved version is available here
IZA Discussion Paper No. 4181
published in: Journal of Public Economic Theory, 2009, 11 (6), 947 - 960
IZA Discussion Paper No. 1588
published in: Journal of Economic Surveys, 2008, 22(1), 31-72