Richards, G., McGreal, R., Hatala, M., & Friesen, N. (2003). The Evolution of Learning Object Repository Technologies: Portals for On-line Objects for Learning. International Journal of E-Learning & Distance Education Revue Internationale Du E-Learning Et La Formation à Distance, 17(3), 67–79. Retrieved from https://ijede.ca/index.php/jde/article/view/297