423 IZA Discussion Papers
IZA Discussion Paper No. 72
published in: Labour Economics, 2003, 10 (1), 73-89
IZA Discussion Paper No. 69
revised version published in: Journal of Economic and Social Measurement, 2007, 32 (1), 15-22
IZA Discussion Paper No. 20
published in: International Migration Review, 2002, 36 (2), 467-491