1. Bick, E. M., and J. W. Copel. 1950. Longitudinal growth of the human vertebra. Journal of Bone and Joint Surgery 32A: 803814.
2. Brain, C. K. 1981. The Hunters or the Hunted? Chicago. University of Chicago Press.
3. Brown, F., J. Harris, R. Leakey and A. Walker. 1985. Early Homo erectus skeleton from west Lake Turkana, Kenya. Nature 316: 788–792.
4. Cihak, R. 1970. Variations of lumbosacral joints and their morphogenesis. Acta Universitatis Carolinae Medica 16: 145–165.
5. Cunningham, D. J. 1886. “Cunningham Memoirs”: Lumbar curve in man and the apes with an account of the topographical anatomy of the chimpanzee and orangutan. Royal Irish Academy, No. II.