1. 1) Ministry of Health, Labour and Welfare, Japan (2006) Ordinance on Industrial Safety and Health (Article 14 amended in 2015). Ministry of Health, Labour and Welfare, the Government of Japan, Tokyo, Japan (in Japanese).
2. 2) Japan Industrial Safety and Health Association (2018) General Guidebook on Industrial Health, 2018 version. 22–23, and 43. Japan Industrial Safety and Health Association, Tokyo (in Japanese).
3. 3) Yamauchi T, Yoshikawa T, Takamoto M, Sasaki T, Matsumoto S, Kayashima K, Takeshima T, Takahashi M (2017) Overwork-related disorders in Japan: recent trends and development of a national policy to promote preventive measures. Ind Health 55, 293–302.
4. 4) Japan Society for Occupational Health (2018) Number of certified associate occupational physician. https://ssl.jaoh-caop.jp/roster.html (in Japanese). Accessed October 27, 2018.
5. 5) Japan Medical Association (2018) Acquisition and renewal course for certification of occupational physicians. http://jmaqc.jp/sang/guide/index.php (in Japanese). Accessed October 27, 2018.