1. U.S. Dept. of Health, Education, and Welfare, “Air Quality Criteria for Sulfur Oxides,” Washington, D.C., 1967.
2. “SO2 in the Atmosphere,”;Urone;Environ. Sci. Tech.,1969
3. Am. Industrial Hygiene Assoc., “Community Air Quality Guides: Sulfur Compounds,” Southfield, Mich., 1970.
4. “Photochemistry of Air Pollution,”;Leighton,1961
5. “The Photochemical Oxidation of Sulfur Dioxide to Sulfur Trioxide and its Effects on Fog Formation,”;Gerhard;Ind. Eng. Chem.,1955