SUM, Sonita, Sajjakaj Jomnonkwao, Thanapong Champahom, Roodheer Beeharry, and Vatanavongs Ratanavaraha. “Measuring the city bus service quality based on users’ perceptions: City bus service in Phnom Penh, Cambodia”. Engineering and Applied Science Research 47, no. 1 (March 17, 2020): 47–55. accessed September 24, 2026. https://ph01.tci-thaijo.org/index.php/easr/article/view/202981.