Kitjaroenpaiboon, W., S. Fahkrajang, P. Fongsarun, and W. Ploylermsaeng. “A Review of Lexico-Grammatical Features and Their Functions in an Academic Discourse”. Journal of Multidisciplinary in Social Sciences, vol. 19, no. 2, May 2023, pp. 99-112, https://so03.tci-thaijo.org/index.php/sduhs/article/view/268406.