S.W, Puasa, Ismail K.N, and Rahim N.S.A. “Oil Removal from Oily Sludge Using Surfactant Technology”. International Journal of Engineering and Technology 7, no. 4.18 (November 27, 2018): 337–341. Accessed April 28, 2025. https://sciencepubco.com/index.php/IJET/article/view/21946.