@techreport{Koopmans2008,
author = {Koopmans, R.},
title= {Tradeoffs between equality and difference: Immigrant integration, multiculturalism, and the welfare state in cross-national perspective},
year = {2008},
URL = {http://193.174.6.11/zkd/mit/pdf/dp_sp_iv_2008-701.pdf},
publisher = {Social Science Research Center Berlin},
address = {Berlin},
number = {WZB discussion paper; SP IV 2008-701},
}