Mahbub, M. A., Romsi, A., Bulqiyah, S. and Firdaus, I. A. (2020) “INFUSING A GAMIFICATION MECHANISM THROUGH DUOLINGO FOR ENGLISH SPEAKING PROFICIENCY: PERCEPTIONS OF THE INDONESIAN EFL INSTRUCTOR AND STUDENTS”, Konstruktivisme : Jurnal Pendidikan dan Pembelajaran, 12(1), pp. 69-80. doi: 10.35457/konstruk.v12i1.894.