H. Abd Wahab, A. Zafiah Mohd Rus, and M. Taufiq Zaliran, “Design of Experiment for In-Situ Synthesis of Waste Vegetable Oils and Synthetic Based Polyurethane (PU) Foam Composites”, IJET, vol. 7, no. 4.34, pp. 413–416, Dec. 2018, doi: 10.14419/ijet.v7i4.34.26898.