Rosman MNI, Ibrahim SA, Muhammad Yusuf Rosman. Optimisation of NaOH Concentration for Sustainable Soap Production Using Waste Cooking Oil. jamea [Internet]. 2025 Dec. 12 [cited 2026 Aug. 12];6(2):49-57. Available from: https://journal.uthm.edu.my/index.php/jamea/article/view/22435