1. Handbook for Monitoring Industrial Wastewaters, U.S. Environmental Protection Agency (August, 1973)
2. M.C. Rand, M.T. Taras, and A.E. Greenberg, Standard Methods for the Examination of Water and Wastewater, 14th Edition, American Public Health Association, Washington, D.C., 1976
3. “Methods for Chemical Analysis of Water and Wastes-1971”, EPA document 16020–07/71, Cincinnati, Ohio (July, 1971)
4. “Manual of Methods for Chemical Analysis of Water and Wastes”, Technology Transfer, U.S. Environmental Protection Agency, Washington, D.C., EPA-625–16–74–003 (1974)
5. American Society of Agronomy and American Society for Testing and Materials, Methods of Soil Analysis, Part 2, Chemical and Microbiological Properties, edited by C.A. Black.