S. Younis, Azzam. “Existence and Uniqueness of the Solution of an Integro-Differential Equation of the Second Order With Boundary Conditions”. Journal of Education and Science 23, no. 4 (December 1, 2010): 100–110. Accessed September 5, 2025. https://ojs.uomosul.edu.iq/index.php/edusj/article/view/42523.