9Pal GP, SherK HH. The vertical stability of the cervical spine[J ]. Spine, 1988, 13:447-449.
10Kumaresan S, Yoganan N, Pintar FA, et al. Contribution of disc degeneration to osteophyte formation in the cervical spine:a biomechanical investigation[ J ]. J Orthop Res, 2001, 19 : 977-984.