4 IZA Discussion Papers
IZA Discussion Paper No. 16930
IZA Discussion Paper No. 11258
revised version published in: Research in Labor Economics, 2020, 48, 253-289.
IZA Discussion Paper No. 8219
published in: Small Business Economics, 2015, 44 (1), 37-54
IZA Discussion Paper No. 1608
published in: RWI-Mitteilungen, 2003/2004, 54/55 (3-4), 287-303