Ghauth, K. I., and N. A. Abdullah. “An Empirical Evaluation Of Learner Performance In E-Learning Recommender Systems And An Adaptive Hypermedia System”. Malaysian Journal of Computer Science, vol. 23, no. 3, Dec. 2010, pp. 141-52, http://jice.um.edu.my/index.php/MJCS/article/view/6407.