A. Halim, K. Khatimah, D. Rachman, A. A. Lubis, S. Sunarti, and R. H. Puspita, “EXPLORING EFL STUDENTS’ EXPERIENCES ON ONLINE-BASED WRITING PORTFOLIO”, acit.j.teach.educ., vol. 1, no. 1, pp. 1–9, Jan. 2019.