Munirah Bt Abdullah, Nor, et al. “Effect of Toxicity Concentration of Waste Lubricating Oil (Hazardous Noxious Substances) on Aquatic Life”. International Journal of Engineering and Technology, vol. 7, no. 3.11, July 2018, pp. 117-20, https://doi.org/10.14419/ijet.v7i3.11.15942.