โพธิรังสิยากรชิดพงษ์. “The Development of Teaching Exercises of English for Business Communication 1”. Journal of Humanities and Social Sciences University of Phayao 4, no. 1 (July 1, 2019): 26 - 36. Accessed October 28, 2021. https://so03.tci-thaijo.org/index.php/Humanties-up/article/view/200319.