1. Ministry of Internal Affairs and Communications/Bureau of Statistics Estimated Population by Age (by Five Age Categories) and Gender http://www.stat.go.jp/data/jinsui/tsuki/index.htm
2. National Institute of Population and Social Security Research Future Total Population and Growth Rates by Age Group (Three Categories), Latest Demographic Statistics 2009 http://www.ipss.go.jp/syoushika/tohkei/Data/Popular2008/T02-07.html
3. Ministry of Health, Labour and Welfare 2008 Simple Life Table http://www.mhlw.go.jp/saikin/hw/life/life08/index.html
4. Management of oral function in elderly from perspective of physical and mental characteristics;Yamane;J Jpn Dent Assoc,2009
5. The relationship between oral health and brain function;Watanabe;J Jpn Dent Assoc,2009