1. Osafune T, Mitsuboshi M, Ito T, Aoki S, Ehara T, Hashiguchi H, Minami K. Analysis of bacterial flora in dohyo soll. Environ Health Prev Med. 2007;12:11–6.
2. Nakagawa Y, Matsusue Y, Nakamura T. An epidemiological study of injuries in student sumo wrestlers. Jpn J Orthop Sports Med. 1998;18:313–9.
3. Nakagawa Y, Hattori Y, Tanaka E, Suzuki T, Gotou T, Okamoto Y, Nakamura T. Orthopaedic study of experienced post-graduate student sumo wrestlers. Japanese J Clin Sports Med. 2005;13:56–60. (in Japanese)
4. Nakagawa Y, Mukai S, Minami K, Hattori Y, Nakamura T. Radiological changes in the cervical spine in freshman collegiate sumo wrestlers. Orthop J Sports Med. 2017 Dec 14;5(12):232596711774421.
5. Kidokoro Y, Kobayashi K, Yamagishi M. Injuries of the spine and the spinal cord in sports. Seikeigeka. 1979;30:629–37. (in Japanese)