1. Harre, E. A., O. W. Livingston, and J. T. Shields. 1974. “World Fertilizer Markets Review and Outlook,” TVA Bulletin Y-70, Tennessee Valley Authority, Muscle Shoals, Alabama (U.S.A.).
2. U.S. Department of Agriculture and Tennessee Valley Authority. 1964. Superphosphate: Its History, Chemistry, and Manufacture, U.S. Government Printing Office, Washington, D.C.
3. Sinte Maartensdijk, A. “Direct Production of Granular Superphosphates and PK Compounds from Sulfuric Acid, Phosphoric Acid, Rock Phosphate, and Potash,” Proceedings of 1976 ISMA Technical Conference The Hague, Netherlands.
4. Yates, L. D., F. T. Nielsson, E. J. Fox, and R. M. Magness. 1953. “Enriched and Concentrated Superphosphate,” Industrial and Engineering Chemistry, 45 (3): 681–690.
5. Brown, G. G., and K. F. Thatcher. 1967. “The Production and Properties of Basic Slag,” Proceedings of the Fertiliser Society ( London ), No. 96.