El-Mowafy, N., S. M. Helal, and M. S. El-Azab. 2020. “Study the Influence of Nonlocal Boundary Condition on the Difference Eigenvalue Problem for Elliptic Partial Differential Equation”. Journal of Informatics and Mathematical Sciences 12 (3):209-22. https://doi.org/10.26713/jims.v12i3.1408.