1. Centers for Disease Control (1988): “National Traumatic Occupational Fatalities, 1980–1985.” Morgantown, WV: National Institute for Occupational Safety and Health, Division of Safety Research.
2. Centers for Disease Control (1980–1985): “National Traumatic Occupational Fatalities.” Morgantown, WV: National Institute for Occupational Safety and Health, Division of Safety Research.
3. Joint Committee, Council of Economic Advisors (1988): “Economic Indicators—March, 1988.” Washington, D.C.
4. Occupational injuries and work experience
5. (1985): “Pennsylvania Farm Fatalities During 1980–1984.” Special Circular 319. University Park, PA: Pennsylvania State University College of Agriculture Cooperative Extension Services.