5 IZA Discussion Papers
IZA Discussion Paper No. 15463
IZA Discussion Paper No. 9892
published in Social Indicators Research
IZA Discussion Paper No. 7603
IZA Discussion Paper No. 6449
revised and updated version published in: Regional Studies, 2017, 51 (7), 1100-1114
IZA Discussion Paper No. 2703
substantially revised version published in: Journal of Development Economics, 2010, 92(2), 215-231