Rimkeeratikul, Sucharat, Mark Zentz, Nittaya Yuangsri, Preeyachat Uttamayodhin, Somrasa Pongpermpruek, and Steven Smith. 2016. “Communication Apprehension in L1 and L2 Among First-Year Students of a Graduate Program for Executives in a Public University”. LEARN Journal: Language Education and Acquisition Research Network 9 (1):1-10. https://so04.tci-thaijo.org/index.php/LEARN/article/view/102657.