 | Nitrates. | (2) |
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 | Nitrates in the upper Santa Ana River Basin in relation to groundwater pollution / R.S. Ayers, R.L. Branson, editors. Berkeley, Calif. : Agricultural Experiment Station, 1973. | |
| Factors affecting the accumulation of nitrate in soil, water, and plants / by Frank G. Viets, Jr. and Richard H. Hageman. Viets, Frank G. (Frank Garfield), 1916- 4n Washington, D.C. : Agricultural Research Service, U.S. Dept. of Agriculture, 1971. | |
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