Haya Haratikka, and Anita Purba. “ESP LEARNERS’ PERCEPTIONS ON USING DUOLINGO”. Multidiciplinary Output Research For Actual and International Issue (MORFAI) 3, no. 4 (January 29, 2024): 1001–1008. Accessed April 20, 2025. https://radjapublika.com/index.php/MORFAI/article/view/1379.