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2. P.J. Peterson, Metals and Micronutrients Uptake and Utilization by Plant, Academic Press, 1983, pp. 50–70.
3. E.J. Underwood, Trace Elements in Human and Animal Nutrition, 4th Ed., Academic Press, New York, 1977.
4. K.M. Hambidge, Elemental Analysis of Biological Material. Technical Rep. Ser., No. 197 IAEA, 1980.