Sartakov, M., Chumak V. A., V., Grekhova, I., & Efanov, M. (2018). 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. Amazonia Investiga, 7(17), 72-78. Retrieved from https://www.amazoniainvestiga.info/index.php/amazonia/article/view/328