T. Priscilla, M. Ardycha Yudha Ramadhani, W. Prayogo, N. Nurjannah, F. Achmad Parmadi, and Z. Arifin, “Optimization of Biodiesel Synthesis Process from Waste Cooking Oil in a Phased Array Ultrasonic Reactor Using Response Surface Methode”, Al-Kimia, vol. 11, no. 2, Dec. 2023.