DE LANGEN, Frank. Sustainability of Open Education Through Collaboration. The International Review of Research in Open and Distributed Learning, [S. l.], v. 19, n. 5, 2018. DOI: 10.19173/irrodl.v19i5.3548. Disponível em: https://www.irrodl.org/index.php/irrodl/article/view/3548. Acesso em: 28 mar. 2024.