HALVERSON, Lisa R.; GRAHAM, Charles R. Learner Engagement in Blended Learning Environments: A Conceptual Framework. Online Learning, Boston, MA, v. 23, n. 2, 2019. DOI: 10.24059/olj.v23i2.1481. Disponível em: https://olj.onlinelearningconsortium.org/index.php/olj/article/view/1481. Acesso em: 3 apr. 2026.