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3. O. A. Biryukova, T. M. Minkina, and N. V. Nikityuk, “Biological Activity of Ordinary Chernozem upon Contamination with the Metals,” in Reclamation of Anthropogenic Landscapes (Novocherkassk, 1997), pp. 105–108 [in Russian].
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5. L. A. Grishina, G. N. Koptsik, and M. I. Makarov, Transformation of Soil Organic Matter (Moscow, 1990) [in Russian].