Tastambek K.Т., Аkimbekov N.Sh., Qiao Xiaohui, Token A.I., Zhubanova A.A. Investigation of physico-chemical and microbial properties of lignite samples: al-Farabi Kazakh National University, Kazakhstan, Almaty. Eurasian Journal of Ecology, v. 55, n. 2, p. 52–60, 7 Oct.2018.