Truong, Hoa Minh. “Perks and Perils of Adult Learners in Communication English Learning at English Language Centers in Vietnam”. English Language Teaching Educational Journal 4, no. 3 (December 31, 2021): 213–224. Accessed December 5, 2025. http://journal2.uad.ac.id/index.php/eltej/article/view/2955.