Klymenko, Ya. V., and V. L. Makarov. “Application of the FD-Method to the Solution of the Sturm-Liouville Problem With Coefficients of Special Form”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 8 (August 25, 2007): 1140–1147. Accessed May 3, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3377.