Revnic, A. “A One-Step Spline Method for the Numerical Solution of Ordinary Differential Equations”. Rev. Anal. Numér. Théor. Approx., vol. 27, no. 2, Aug. 1998, pp. 339-50, https://ictp.acad.ro/jnaat/journal/article/view/1998-vol27-no2-art15.