Adorni, Giovanni, Mauro Coccoli, Gianni Vercelli, and Giuliano Vivanet. “Topic Maps E XTM Per l’e-Learning”. Journal of e-Learning and Knowledge Society 3, no. 3 (October 16, 2012). Accessed September 20, 2020. https://www.je-lks.org/ojs/index.php/Je-LKS_EN/article/view/756.