1. DeVries HA EMG fatigue curves in postural muscles. A possible etiology for idiopathic low back pain. Amer J Phys Med 47: 175, 1968
2. Dixon HH, O'Hara M., Peterson RD: Fatigue contracture of skeletal muscle. Northwest Med 66: 813-816, 1967
3. Kraus H.: Preventive aspects of physical fitness. New York J Med 64: May, 1964
4. Back Pain and Tension Syndromes in a Sedentary Profession
5. Sainsbury P. , Gibson TG: Symptoms in anxiety and tension and the accompanying physiological changes in the muscular system. J Neurol Neurosurg Psychiat 17: August, 1954