1. 1) Japan Ministry of Health, Labour and Welfare. An outlook on the result of survey on health status of workers, 2002. http://www.mhlw.go.jp/toukei/itiran/roudou/saigai/anzen/kenkou02/index.html. Accessed February 27, 2006 (in Japanese).
2. 2) National Police Agency. Statistics of the National Police Agency, 2004. http://www.npa.go.jp/toukei/chiiki4/jisatu.pdf. Accessed December 28, 2005 (in Japanese).
3. 3) Nakamura K, Simomitsu T, Kamiyama A (1997) The survey on the actual condition of stress assessment at work place. In: The report on the prevention of work related diseases, 105-10, Ministry of Labour, Tokyo (in Japanese).
4. 4) Hayashi T (2002) Stress management for office workers. San Ei Shi 44, 175-9 (in Japanese).
5. 5) Watanabe M (2003) Stress management in manufacturing industries. San Ei Shi 45, 1-6 (in Japanese).