Fenta , Hibist Bazezew, and Getachew Adamu Derese. “Numerical Solution of Second Order Initial Value Problems of Bratu-Type Equations Using Sixth Order Runge-Kutta Seven Stages Method”. (IJCSAM) International Journal of Computing Science and Applied Mathematics, vol. 5, no. 1, Feb. 2019, pp. 10-14, https://journal.its.ac.id/index.php/ijcsam/article/view/4628.