S. Mahmood, Ammar, and عمار. “On the Rings of Differential Operators”. AL-Rafidain Journal of Computer Sciences and Mathematics 3, no. 1 (June 25, 2025): 117–126. Accessed August 5, 2025. https://rjps.uomosul.edu.iq/index.php/csmj/article/view/20043.