Esteban, Allan Jay. “Theories, Principles, and Game Elements That Support Digital Game-Based Language Learning (DGBLL): A Systematic Review”. International Journal of Learning, Teaching and Educational Research 23, no. 3 (March 30, 2024): 1–22. Accessed June 27, 2026. http://www.ijlter.net/index.php/ijlter/article/view/1882.