Suksiripakonchai, Watthana. “ICAO Language Proficiency Requirements and Training Guidance for Thailand”. Journal of Multidisciplinary in Social Sciences 8, no. 1 (January 23, 2013): 175–184. accessed March 13, 2025. https://so03.tci-thaijo.org/index.php/sduhs/article/view/5111.