Natela Khetsuriani, Esma Usharauli, Elza Topuria, Tamar Shatakishvili, and Maka Kopaleishvili. “NATURAL BITUMEN OF GEORGIAN”. World Science, Vol. 1, no. 2(54), Feb. 2020, pp. 15-19, doi:10.31435/rsglobal_ws/28022020/6924.