4 IZA Discussion Papers
IZA Discussion Paper No. 15686
IZA Discussion Paper No. 11683
published online in: Journal of Human Resources, 13 October 2021
IZA Discussion Paper No. 11347
IZA Discussion Paper No. 8411
revised version published in: Journal of the Royal Statistical Society, Series A, 2018, 181 (4), 1057 - 1074