Ubonnoi, P., and P. Yangklang. “The Development of English Speaking Skills Using a Task-Based Learning Approach Focused on Selling Local Products for the Ninth Grade Students”. Journal of Education Studies, vol. 49, no. 4, Dec. 2021, p. EDUCU4904013(13 pages) doi: 10.14456/educu.2021.72, https://so02.tci-thaijo.org/index.php/EDUCU/article/view/253621.