M. Salman, Israa, and Eman A. Abdul-Razzaq. “Solving Nonlinear Second Order Delay Eigenvalue Problems by Least Square Method”. Ibn AL-Haitham Journal For Pure and Applied Sciences 33, no. 4 (October 20, 2020): 59–64. Accessed March 28, 2025. https://jih.uobaghdad.edu.iq/index.php/j/article/view/2509.