Aroonsrimorakot, S. “Pollution Reduction and Increasing of Efficiency Use of Fuel by Building Up the Bus Preventive Maintenance System and Environmental Management System”. Environment and Natural Resources Journal, vol. 8, no. 1, Apr. 2017, pp. 1-8, https://ph02.tci-thaijo.org/index.php/ennrj/article/view/82557.