Siahaan, Desta Gloria, Maria Hendrika Kristen Indi Nahak, and Edmundus Bouk. “Duolingo Application As A Mean to Deepen Understanding of English Vocabulary by Students of English Educational Department Timor University”. Buletin Poltanesa 25, no. 2 (December 6, 2024): 208–216. Accessed January 6, 2025. https://e-journal.politanisamarinda.ac.id/index.php/tanesa/article/view/3189.