Caeiro, M., Fontenla, J., & Llamas, M. (2011). What are my students doing? Introducing ELENA, the E-Learning Event Notification Architecture. Cadernos De Informática, 6(1), 171–178. Recuperado de https://seer.ufrgs.br/index.php/cadernosdeinformatica/article/view/v6n1p171-178