Khojiyeva Rukhsora Baxtiyorovna, Bokiyeva Shakhnoza Komilovna. “Comprehensive Scheme for Processing Used Oils and Lubricants”. International Journal of Advanced Science and Technology, Vol. 29, no. 9s, May 2020, pp. 4156 -59, http://sersc.org/journals/index.php/IJAST/article/view/16782.