Pongsavake Anekjumnongporn, Tunyaluk Anekjumnongporn, and Phurinut Banlang. “English Competency of Hotel Housekeeping Department’s Staffs in Bangkok”. KKU Research Journal (Graduate Studies) Humanities and Social Sciences, vol. 9, no. 1, Apr. 2021, pp. 1-9, https://so04.tci-thaijo.org/index.php/gskkuhs/article/view/220475.