Nguyen, Thuy Thi Thanh, and Yukawa Takashi. “Mobile Devices Applied in Self-Studying English As a Foreign Language Among Non-Native Students in Vietnam and Japan”. International Journal of Interactive Mobile Technologies (iJIM), vol. 15, no. 09, May 2021, pp. pp. 70-87, doi:10.3991/ijim.v15i09.19993.