1. Lehr, J.R., “Fluorine Chemical Redistribution in Relation to Gypsum Storage Pond Systems,” presented at the 1978 Fertilizer Institute Environmental Symposium, March 6-8, 1978, New Orleans, La.
2. “Process for the Production of Phosphoric Acid and Calcium Fluoride”, U.S. Patent 5,531,975, William R. Erickson and Leif E. Bouffard, Phosphate Engineering and Construction Co., Inc.
3. U.S. Code of Federal Regulations, Title 40 CFR, Part 60, Subpart T.
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