S. I V, N. A E, K. M M, and S. Yu.L, “Efficient carbonaceous sorbent based on the waste sludge of oil extraction industry for purifying wastewater from petroleum products”, IJET, vol. 7, no. 2.23, pp. 266–269, Apr. 2018, doi: 10.14419/ijet.v7i2.23.11928.