9 IZA Policy Papers
IZA Policy Paper No. 207
IZA Policy Paper No. 178
IZA Policy Paper No. 89
published in: International Encyclopedia of the Social & Behavioral Sciences, 2nd edition, 2015, Vol. 6, 765-772
IZA Policy Paper No. 73
published in: IZA Journal of European Labor Studies, 2014, 3:10, [Open Access]
IZA Policy Paper No. 44
IZA Policy Paper No. 26