Borjas, J. B. (2001) Heaven's door: immigration policy and the American economy.Princeton, Princeton University Press.
2.
Brücker, H. H. et al. (2002) ‘Managing migration in the Welfare State’, in Boeri, et al.
3.
Hanson, G., K. F. Sheve et al. (2002) ‘Immigration and the US economy’, in T. Boeri, G. Hanson and B. McCormick Immigration policy and the welfare system, Oxford: Oxford University Press
4.
OECD (1997) Trends in international migration, Paris: Sopemi.
5.
Smith, J. and B. Edmonston (1997) The New Americans: Economic, demographic and fiscal effects of immigration, Washington DC: National Academy Press.
6.
Zimmerman, K. (1995) ‘Wage and mobility effects of trade and migration’, London, CEPR Discussion Paper No 1318, January 1995.