Amangeldykyzy, A., Kopobaуeva A., N. Askarova, D. Ozhigin, and V. Portnov. “Study of Rare Earth Elements in the Coals of the Shubarkol Deposit”. Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex Use of Mineral Resources, vol. 319, no. 4, Oct. 2021, pp. 48-56, doi:10.31643/2021/6445.40.