American Medical Association, National Institute for Occupational Safety and Health (U.S.), American Medical Association Congress on Occupational Health, Hatch, L. L., Doege, T. C., & Wheater, R. H. (1978). Occupational safety and health symposia, 1977. U.S. Dept. of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Division of Technical Services ; For sale by the Supt. of Docs., U.S. G.P.O..

American Medical Association, National Institute for Occupational Safety and Health (U.S.), American Medical Association Congress on Occupational Health, Loren L. Hatch, Theodore C. Doege, và Robert H. Wheater. Occupational Safety and Health Symposia, 1977. Cincinnati, Ohio : Washington, D.C.: U.S. Dept. of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Division of Technical Services ; For sale by the Supt. of Docs., U.S. G.P.O., 1978.

American Medical Association, et al. Occupational Safety and Health Symposia, 1977. U.S. Dept. of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Division of Technical Services ; For sale by the Supt. of Docs., U.S. G.P.O., 1978.