Adorni, Giovanni, Diego Brondo, and Giuliano Vivanet. “A Formal Instructional Model Based on Concept Maps”. Journal of e-Learning and Knowledge Society 5, no. 3 (December 21, 2009). Accessed March 29, 2020. https://www.je-lks.org/ojs/index.php/Je-LKS_EN/article/view/350.