1. Aging and high-frequency hearing sensitivity;Wiley;J Speech Lang Hear Res.,1998
2. Presbycusis;Gates;Lancet.,2005
3. Result of census and the population estimates. Ministry of Internal Affairs and Communications, Japan. Available at: https://www.stat.go.jp/data/topics/topi1211.html (accessed Sep 9, 2020)
4. Japan: super-aging society preparing for the future;Muramatsu;Gerontologist,2011
5. United Nations, Department of Economic and Social Affairs, Population Division (2019). World Population Prospects 2019: Highlights (ST/ESA/SER.A/423).