Praimahaniyom, T., and B. Chairinkom. “Developing GROUPS Model for Learning English Communication Skills: Kamphaeng Phet Rajabhat University, Maesot”. Trends of Humanities and Social Sciences Research, vol. 8, no. 2, Nov. 2020, pp. 16-42, https://so03.tci-thaijo.org/index.php/Humanties-up/article/view/201836.