altaher, ahsan, and Hameeda Oda Al-Humedi. “ A Combination of the Orthogonal Polynomials With Least – Squares Method for Solving High-Orders Fredholm-Volterra Integro-Differential Equations”. Al-Qadisiyah Journal of Pure Science 26, no. 1 (November 30, 2020): Math 20-38. Accessed January 18, 2026. https://www.journalsc.qu.edu.iq.51-77-64-103.cpanel.site/index.php/JOPS/article/view/1207.