References
3. U.S. Environmental Protection Agency, Compilation of Air Pollutant Emissions Factors Volume 1: Stationary Point and Area Sources, Fifth Edition with Supplements, January 1995, Document No. AP-42. (Section 8.9 Phosphoric acid, July 1993).
4. Atmospheric Emissions From Thermal Process Phosphoric Acid Manufacture, AP-48, U. S. Environmental Protection Agency, Research Triangle Park, NC, October 1968.
5. National Emission Standards for Hazardous Air Pollutants Phosphoric Acid Manufacturing and Phosphate Fertilizers Production; Final Rule. Federal Register, 40 CFR Parts 9 and 63, Vol. 64, No. 111, June 10, 1999.
6. Fluorides. Committee on Biologic Effects of Atmospheric Pollutants. National Academy of Sciences. Washington, D.C. 1971.