Tawfiq, Luma. N. M., and Reem. W. Hussein. “On Solution of Regular Singular Initial Value Problems”. Ibn AL-Haitham Journal For Pure and Applied Sciences 26, no. 2 (April 27, 2017): 257–264. Accessed November 24, 2024. https://jih.uobaghdad.edu.iq/index.php/j/article/view/474.