Sopa, Narongrit, Poonsak Sirisom, and Ketsiri Jampeehom. 2017. “English Language Competency Development of Tour Guides in Maha Sarakham Province in Preparation for the ASEAN Community by Integrating Three Concept-Centered Instructional Models and Using English in Actual Situations”. African Journal of Pedagogy and Curriculum 4 (November): 95-101. https://doi.org/10.63569/6n87m238.