Kandeel, Refat Abdelsamsd Abouelgheat. “Analysis Of Errors In Limits Of Trigonometric Functions Among Students at King Saud University”. Advances in Social Sciences Research Journal 4, no. 3 (February 15, 2017). Accessed December 8, 2025. https://www.journals.scholarpublishing.org/index.php/ASSRJ/article/view/2683.