Gemechu, Nebiyu, Milkessa Gebeyehu, and Tamirat Abebe. “Multipole Expansion of Relativistic Electric Potential”. Ethiopian Journal of Education and Sciences 15, no. 1 (February 27, 2020): 60-68. Accessed May 8, 2024. https://journals.ju.edu.et/index.php/ejes/article/view/1125.