Duressa, G. F., G. G. Kiltu, T. A. Bullo, and A. G. Kassaye. “Non-Polynomial Spline Method for Solving Nonlinear Two Point Boundary Value Problems”. Ethiopian Journal of Education and Sciences, Vol. 15, no. 1, Feb. 2020, pp. 42-59, http://ejhs.ju.edu.et/index.php/ejes/article/view/1123.