Nadir, Narmeen. “Series Solution for Single and System of Non-Linear Volterra Integral Equations”. Cihan University-Erbil Scientific Journal 4, no. 2 (July 20, 2020): 6-8. Accessed April 19, 2024. https://journals.cihanuniversity.edu.iq/index.php/cuesj/article/view/205.