Ichim, Ion, and Grigore Albeanu. “Cubic Trigonometric Spline Functions of Interpolation and Applications”. Rev. Anal. Numér. Théor. Approx. 28, no. 2 (August 1, 1999): 145–161. Accessed April 19, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1999-vol28-no2-art5.