1. Ajtay, G. L., P. Ketner, and P. Duvigneaud. 1979. Terrestrial primary production and phytomass. In The Global Carbon Cycle, B. Bolin, E. T. Degens, S. Kempe, and P. Ketner, eds. pp. 129–182. New York: Wiley.
2. Ecol. Stud 34;HP Bailey,1979
3. Durran, D. R., M. J. Meldgin, M. K. Liu, T. Thoem, and D. Henderson. 1979. A study of long range air pollution problems related to coal development in the northern Great Plains. Atmos. Environ. 13: 104–1037.
4. FAO. 1979. 1978 FAO Production Yearbook. Vol. 32. Rome: Food and Agriculture Organization of the United Nations.
5. Guderian, R., and K. Kueppers. 1980. Response of plant communities to air pollution p. 187–199. In Effects of Air Pollutants on Mediterranean and Temperate Forest Ecosystems, P. R. Miller, ed. Berkeley, Calif.: U.S.D.A. Forest Service Gen. Tech. Rep. PSW-43.