1. Department of Sociology and Human Geography, University of Oslo , 0317 Oslo, Norway
2. Department of Sociology, University of Tübingen , 72074 Tübingen, Germany
3. Institut des Sciences Sociales, University of Lausanne , 1015 Lausanne, Switzerland
4. Swedish Institute for Social Research (SOFI), Stockholm University , 10691 Stockholm, Sweden
5. Max Planck Institute for Demographic Research, 18057 Rostock; Department of Sociology, Stockholm University, 10691 Stockholm; Swedish Collegium for Advanced Study , 75238 Uppsala, Sweden
6. Department of Sociology, Princeton University , Princeton, NJ 08544, USA ; , Cambridge, MA 02138, USA
7. National Bureau for Economic Research , Princeton, NJ 08544, USA ; , Cambridge, MA 02138, USA
8. Political Science Department, New York University , New York, NY 10012, USA
9. Institute of Behavioral Science and Institute for Behavioral Genetics, University of Colorado , Boulder, CO 80303, USA