3 IZA Discussion Papers
IZA Discussion Paper No. 7198
published in: Stata Journal, 2014, 14 (2), 398-406
IZA Discussion Paper No. 6031
published in: Econometric Reviews, 35(6), 2016, 1075-1098
IZA Discussion Paper No. 4928
published in: Jahrbücher für Nationalökonomie und Statistik, 2011, 231 (4), 546-557