Hidayat D. THE EFFECTIVENESS OF DUOLINGO IN IMPROVING VOCABULARY MASTERY AMONG FOURTH-GRADE STUDENTS. AIJES [Internet]. 10 Juli 2025 [dikutip 13 Oktober 2025];4(2):641-7. Tersedia pada: https://ejurnal.stkipddipinrang.ac.id/index.php/jse/article/view/306