1. Mirel LB, MS and Carper K, MEd, Trends in Health Care Expenditures for the Elderly, Age 65 and Over: 2001, 2006, and 2011, Agency for Healthcare Research and Quality, January 2014.
2. World Report on Disability, World Health Organization and World bank, 2011 retrieved from website
https://www.worldbank.org/en/topic/disability
3. United Nations, Department of Economic and Social Affairs, Population Division (2017). World Population Ageing 2017 – Highlights, (ST/ESA/SER.A/397.
4. He W, Goodkind D, and Kowal P, An Aging World: 2015- International Population Reports, issued March 2016 by United States Census Bureau.
5. Gil-Garcia JR, Helbig N, Ojo A. Being smart: Emerging technologies and innovation in the public sector. Gov Inf Q. 2014;31:I1–8 retrieved from the website
https://doi.org/10.1016/j.giq.2014.09.001
.