M. Kamal, Nurul Atiqah Aisyah, and Siti Aida Ibrahim. “Producing a Liquid Soap by Adding Lemon Extract from Used Cooking Oil for Multipurpose Cleaning Use”. Research Progress in Mechanical and Manufacturing Engineering 5, no. 1 (October 17, 2024): 378–386. Accessed April 8, 2026. https://penerbit.uthm.edu.my/periodicals/index.php/rpmme/article/view/16803.