Thi Lai, T., Thi Hong Lien, N. ., & Ngoc Vu, N. (2021). FLIPGRID APP FOR TEACHING SPEAKING SKILLS: STUDENTS’ PERCEPTIONS AND PERFORMANCE IMPACT. VNU Journal of Foreign Studies, 37(6), 155-167. https://jfs.ulis.vnu.edu.vn/index.php/fs/article/view/4928