1. Appalachian Land Ownership Task Force (1981).Land Ownership Patterns and Their Impacts on Appalachian Communities: A Survey of 80 Counties. PB-81-194755 (NTIS). Washington, D. C.
2. Bjornstad, D.J., and Stuckwish, D. N. (1980). County coal projections 1975?2000 prepared for the National Coal Utilization Assessment. ORNL/TM-6752. Oak Ridge National Laboratory, Oak Ridge, Tenn.
3. Cohen, B. L., and Lee, I. S. (1979). A catalog of risks.Health Physics 36: 707?722.
4. Comptroller General of the United States. (1979). Excessive truck weight; an expensive burden we can no longer support. Report to Congress by the General Accounting Office. CED 79-94. U.S. Government Printing Office, Washington, D. C.
5. Durnin, J. V. G. A., and Passmore, R. (1967).Energy, Work and Leisure. Heinemann Educational Books, London.