Tawfiq, Luma. N. M., and Heba. W. Rasheed. “On Solution of Regular Singular Ordinary Boundary Value Problem”. Ibn AL-Haitham Journal For Pure and Applied Sciences 26, no. 2 (April 27, 2017): 249–256. Accessed November 24, 2024. https://jih.uobaghdad.edu.iq/index.php/j/article/view/473.