H. ISMAIL, T.; O. HAMAD, I. A Generalized Curvature of a Generalized Envelope. AL-Rafidain Journal of Computer Sciences and Mathematics, [S. l.], v. 6, n. 2, p. 39–47, 2009. DOI: 10.33899/csmj.2009.163795 . Disponível em: https://csmj.uomosul.edu.iq/index.php/csmj/article/view/36415. Acesso em: 17 dec. 2025.