Fadhil Hasif, Ahmad, and Ramiaida Darmi. “Comparative Analysis of Duolingo and Memrise for English Language Learning”. Conference on English Language Teaching 4, no. 1 (June 26, 2024): 137–145. Accessed July 3, 2024. https://proceedings.uinsaizu.ac.id/index.php/celti/article/view/1017.