1. Basten S Sobotka T Zeman K (2014) Future fertility in low fertility countries. World Population and Human Capital in the 21st Century, eds Lutz W Butz WP S KC (Oxford Univ Press, Oxford, UK), pp 39–146.
2. Lutz W, Vaupel JW, Ahlburg DA eds. (1999) Frontiers of Population Forecasting. A Supplement to Population and Development Review (1998) Vol. 24. (The Population Council, New York).
3. United Nations (2015) World Population Prospects: The 2015 Revision, Key Findings and Advance Tables (Department of Economic and Social Affairs, Population Division, New York, NY). Available at https://esa.un.org/unpd/wpp/publications/files/key_findings_wpp_2015.pdf. Accessed February 1, 2016.
4. The coming acceleration of global population ageing
5. Lutz W, Butz WP, S KC, eds. (2014) World Population and Human Capital in the 21st Century (Oxford Univ Press, Oxford, UK).