1. Epidemiology and diagnosis in low back injury;Nordby;Occup Health Safety,1981
2. Prevalence of Selected Impairments;National Health Survey;DHHS Publication 81,1562
3. Legal ramifications of the medical definition of back disease;Hadler;Ann Intern Med,1978
4. Epidemiology and impact of low back pain;Kelsey;Spine,1980
5. The biomechanical advantage of lordosis and hip extension for upright activity;Farfan;Spine,1978