Nguyễn D. A SURVEY OF QUESTION TYPES IN ELEMENTARY-LEVEL VIETNAMESE LANGUAGE TEXTBOOKS FOR FOREIGN LEARNERS: FREQUENCY OF OCCURRENCE AND EXPLANATION OF STRUCTURE AND MEANING. Tạp chí Khoa học. 2025;22(6). Accessed July 15, 2025. https://journal.hcmue.edu.vn/index.php/hcmuejos/article/view/5061