Chommanee Patthanapiradej. (1988) Comparative effect of flexion and extension exercise in mechanical back pain patients. Mahidol University,:ม.ป.ท.Chommanee Patthanapiradej. 1988. Comparative effect of flexion and extension exercise in mechanical back pain patients. ม.ป.ท.:Mahidol University,;Chommanee Patthanapiradej. Comparative effect of flexion and extension exercise in mechanical back pain patients. ม.ป.ท.:Mahidol University, 1988. Print.