3 IZA Discussion Papers
IZA Discussion Paper No. 10132
IZA Discussion Paper No. 1742
published in: B.E. Journal of Economic Analysis and Policy: Contributions to Economic Analysis and Policyy, 2006, 5 (1), Article 10
IZA Discussion Paper No. 704
published in: Industrial and Labor Relations Review, 2005, 58 (2), 219-237