HALACHEV, Petar. Gamification as an e-learning tool: A Literature Review. E-Learning Innovations Journal, [S. l.], v. 2, n. 2, p. 4–20, 2024. DOI: 10.57125/ELIJ.2024.09.25.01. Disponível em: https://el-journal.org/index.php/journal/article/view/17. Acesso em: 6 jun. 2026.