1. Administration, S. S. (1937). Social Security Bulletin: Social Security Administration. Available: https://www.ssa.gov/policy/docs/ssb/v73n2/ssb-v73n2.pdf . Accessed 10 December 2016.
2. Administration, S. S. (2002). Social Security Programs Throughout the World: Asia and the Pacific, 2008 (Vol. 13, Vol. 11801): Government printing office. Available: https://www.ssa.gov/policy/docs/progdesc/ssptw/2002-2003/asia/india.pdf . Accessed 10 December 2016.
3. Alam, M., James, K., Gridhar, G., Sathyanarayana, K., Kumar, S., Raju, S. S., et al. (2012). Report on the status of elderly in select states of India, 2011. United Nations Population Fund (India). Available: http://www.India.unfpa.org/drive/AgeingReport_2012_F.pdf . Accessed 16 January 2016.
4. Angrist, J., & Krueger, A. B. (2001). Instrumental variables and the search for identification: From supply and demand to natural experiments. Journal of Economic Perspectives, 15(4), 69–85. Available: https://economics.mit.edu/files/18 . Accessed 24 December 2016.
5. Atchley, R. C. (1976). The sociology of retirement. New York: Halsted Press.