GARCÍA-PEÑALVO, F. J. An up-to-date survey of e-learning systems. Education in The Knowledge Society, [S. l.], v. 6, n. 2, 2022. DOI: 10.14201/eks.18184. Disponível em: https://revistas.usal.es/tres/index.php/eks/article/view/18184. Acesso em: 18 apr. 2025.