D.W. GORE. The Application of Social Presence to Improve Retention in Online Problem-Based Course. Journal of Online Engineering Education, [S. l.], v. 3, n. 2, 2012. Disponível em: https://www.onlineengineeringeducation.com/index.php/joee/article/view/51. Acesso em: 19 apr. 2024.