H. Ismail, Tahir, طاهر, Ibrahim O. Hamad, and إبراهیم. “A Nonstandard Generalization of Envelopes”. AL-Rafidain Journal of Computer Sciences and Mathematics 5, no. 2 (June 25, 2025): 73–83. Accessed August 7, 2025. https://ojs.uomosul.edu.iq/index.php/csmj/article/view/19936.