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Sartakov, M. P.; Chumak V. A., V. A.; Grekhova, I. V.; Efanov, M. V. The Study of the Chemical Composition of Humic Acids of Initial and Heat-Treated Sapropels of Lakes of the Surgut District of the Khanty-Mansi Autonomous Okrug – Yugra. AmazInv 2018, 7, 72-78.