1) National Safety Council (2011) Injury facts 2011 Ed., National Safety Council, Itasca Illinois.
2) The Guardian (2014) What do people die of? Mortality rates and data for every cause of death in 2011 visualized, Data blog -Facts are sacred, http:// www.theguardian.com/news/ datablog/2012/nov/06/deaths-mortality- rates- cause-death-2011#. Accessed July 11, 2014.
3) Ministry of Health Labour and Welfare (2014) Vital Statistics of Japan 2012, 302-303, Health Labour and Welfare Statistics Association, Tokyo. (in Japanese).
4) Svanström L (1974) Falls on stairs: an epidemiological accident study. Scand J Soc Med 2, 113-20.
5) Wyatt JP, Beard D, Busuttil A (1999) Fatal falls down stairs. Injury 30, 31-4.