1. Japan: Super-Aging Society Preparing for the Future
2. Public debt and economic growth in an aging Japan;Ihori,2006
3. Population Estimate
http://www.stat.go.jp/data/jinsui/2017np/pdf/2017np.pdf
4. The effects of the low birth rate on the Japanese social security system;Fukawa;Jpn. J. Soc. Secur. Policy,2008
5. World Report on Ageing and Health
https://www.who.int/ageing/events/world-report-2015-launch/en/