Hassan, I. M., and S. A. Alhswem. “On the System of Nonlinear Elliptic Equations With Nonlocal Boundary Conditions of Neumnna Type”. The Libyan Journal of Science 23, no. 1 (February 4, 2022): 31–39. Accessed April 19, 2026. https://journals.uot.edu.ly/index.php/ljs/article/view/119.