1. Giaser M. Greenberg L. and Field F. Mortality and morbidity during a period of high levels of air pollution Nov. 23-25 1966. Arch. Environ. Health 15: 684 (1967).
2. Schronk H. H. etal Air pollution in Donora Pa.: Epidemiology of an unusual smog episode of October 1948. P. H. Bulletin 306 Fed. Sci. Agency. Div. Ind. Hyg. PHS U.S. Dept. HEW Washington D.C. 1949.
3. The London fog of December 1966;Scott J. A;Med. Office.,1966
4. Health Consequences of Sulfur Oxides: A Report from Chess 1970-1971. U. S. Environmental Protection Agency Research Triangle Park. N. C. 1974.
5. Graybill F. An Introduction to Linear Statistical Models Vol. 1. McGraw-Hill New York 1961.