Dahlia, Agus, and Rahma Qudsi. “Determine the Solution of Delay Differential Equations Using Runge-Kutta Methods With Cubic-Spline Interpolation”. (IJCSAM) International Journal of Computing Science and Applied Mathematics, vol. 9, no. 1, Feb. 2023, pp. 1-3, https://journal.its.ac.id/index.php/ijcsam/article/view/4658.