1. Bluestone, I. R., Montgomery, J. V., & John, D. O. (Eds.) (1990). The ageing of the American work force: Problems, programs, policies, Detroit, MI: Wayne State University Press.
2. Social, economic, and health aspects of low fertility;Campbell,1990
3. Census and Statistics Department (1997). Hong Kong population projection 1997–2016. Census and Statistics Department, Hong Kong Special Administrative Region.
4. Can immigration slow U.S. population aging;Espenshade;Journal of Policy Analysis and Management,1994
5. Family Planning Association of Hong Kong (1998). Knowledge, attitude and practice survey. Family Planning Association of Hong Kong.