7Terrett AC, Vernon H. Manipulation and pain tolerance. A controlled study of the effect of spinal manipulation on paraspinal cutaneous pain tolerance levels.Am J Phys Med 1984;63(5):217-25
8Dai LY, Xu YK, Zhang WM, et al. The effect of flexion-extension motion of the lumbar spine on the capacity of the spinal canal. An experimental study.Spine 1989;14(5):523-5
9Schlegel JD,Champaine J,Taylor MS,et al.The role ff distrection improving the Space available in the lumber stenotic canal and formen.Spine 1994;19(18):2041