Adam, Ibrahim Khalil, A.Rashid A.Aziz, Suzana Yusup, Morgan Heikal, and Ftwi Yohaness Hagos. 2016. “Optimization of Performance and Emissions of a Diesel Engine Fuelled With Rubber Seed- Palm Biodiesel Blends Using Response Surface Method”. Asian Journal of Applied Sciences 4 (2). https://ajouronline.com/index.php/AJAS/article/view/3584.