Azrin, Alif Izzuddin, and Mohammad Fahmi Abdul Ghafir. “Investigation of Different Emissions Tax Calculation Methods for Kuala Lumpur International Airport”. Progress in Aerospace and Aviation Technology, vol. 4, no. 2, Dec. 2024, pp. 51-59, https://penerbit.uthm.edu.my/ojs/index.php/paat/article/view/16789.