1. 1) National Institute of Population and Social Security Research: http://www.ipss.go.jp/syoushika/tohkei/suikei07/suikei.html (access 25 June 2008).
2. 2) Ministry of Health, Labour and Welfare: Summary of vital statistics, http://www.mhlw.go.jp/english/database/db-hw/populate/pop4.html (access 23 March 2009).
3. 3) Matsuda S: The health and social system for the aged in Japan. Aging Clin Exp Res 14, 265-270 (2002).
4. 4) Ministry of Health, Labour and Welfare: Report of Long-term Care Insurance 2006, http://www.mhlw.go.jp/topics/kaigo/osirase/jigyo/06/dl/01.pdf (access 23 October 2008).
5. 5) National Federation of Health Insurance Societies: Health Insurance, Long-term care insurance and Health insurance societies in Japan 2003, NFHIS (2003).