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2. N. A. Kireeva, V. V. Vodop’yanov, and A. M. Miftakhov, Biological Activity of Oil-Contaminated Soils [in Russian], Gilem, Ufa (2001).
3. B. A. Dospekhov, Procedure for Field Testing (With Fundamentals of Statistical Processing of Results of Investigations) [in Russian], 2nd edition, revisions and additions, Kolos, Moscow (1973).