3 IZA Discussion Papers
IZA Discussion Paper No. 14293
published in: Journal of Applied Econometrics, 2021, 36 (7), 1065-1073.
IZA Discussion Paper No. 5062
revised version published in: Review of Income and Wealth, 2012, 58 (4), 622-647
IZA Discussion Paper No. 2849
published in: Allgemeines Statistisches Archiv/Journal of the German Statistical Society, 2007, 1 (3-4), 247-261