Abdul Hassan, Alia Karim, and Ahmed Bahaa Aldeen Abdulwahhab. 2018. “The Proposed Collaborative Filtering Recommender System Based on Implicit and Explicit User’s Preferences”. Iraqi Journal of Science 59 (2A): 771-85. https://www.ijs.uobaghdad.edu.iq/index.php/eijs/article/view/282.