Venegas Muggli, Juan Ignacio, and Werner Westermann. “Effectiveness of OER Use in First-Year Higher Education Students’ Mathematical Course Performance: A Case Study ”. The International Review of Research in Open and Distributed Learning 20, no. 2 (April 30, 2019). Accessed April 28, 2024. https://www.irrodl.org/index.php/irrodl/article/view/3521.