4 IZA Discussion Papers
IZA Discussion Paper No. 3254
revised version published in: Journal of Econometrics, 2013, 175(2), 94-115
IZA Discussion Paper No. 899
IZA Discussion Paper No. 876
published in: Applied Economics Quarterly, 2003, 49 (2), 93-121
IZA Discussion Paper No. 531
published in: Economic Modelling, 2003, 20 (2), 237-273