2 IZA Discussion Papers
IZA Discussion Paper No. 2146
published in T.J. Hatton. K. H. O'Rourke and A. M. Taylor (eds.), The New Comparative Economic History: Essays in Honor of Jeffrey G. Williamson, Cambridge Mass: MIT Press, 2007
IZA Discussion Paper No. 1230
published in: D. Snower (ed.) Labour Mobility and the World Economy, Kiel: Kiel Institute for World Economics, 2005