1. Department of Social and Political Sciences, Università Commerciale Luigi Bocconi, Milan 20136, Italy
2. Carlo F. Dondena Centre for Research on Social Dynamics and Public Policy, Università Commerciale Luigi Bocconi, Milan 20136, Italy
3. School of Public and International Affairs and Office of Population Research, Princeton University, Princeton NJ 08544
4. Department of Sociology, Harvard University, Cambridge, MA 02138
5. Department of Sociology, University of Pennsylvania, Philadelphia, PA 19104
6. Department of Sociology and Office of Population Research, Princeton University, Princeton NJ 08544
7. Tokyo College, University of Tokyo, Tokyo 113-8654, Japan
8. Department of Sociology and Anthropology, National University of Singapore, Singapore 117570, Singapore
9. Yong Loo Lin School of Medicine, Department of Paediatrics, National University of Singapore, Singapore 119228, Singapore
10. Agency for Science, Technology and Research, Singapore