223 IZA Discussion Papers
IZA Discussion Paper No. 459
revised version published in: German Economic Review, 2005, 6 (4), 445-469
IZA Discussion Paper No. 259
published in: Journal of Happiness Studies, 2001, 2 (2), 147-172
IZA Discussion Paper No. 124
published in: Review of Income and Wealth, 2001, 47(3), 379-398