1. Quoted by Muenchow et al, Medizin und;Jaros, M.; Cheh, U.M.;Sport,1965
2. Studies of Spondylolysis found among Weight-lifters;Kotani, P.T.; Ichikawa, N.; Wakabayashi, W.; Yoshii, T.; Koshimune, M.;Brit. J. Sports Med,1970
3. 1969 "The Spine in Weight-lifters";Muenchow, H.; Alber, H.;Medizin und Sport
4. D. Brunner and E. Jokl. 1977.
5. of "Medicine and Sport