Ronto, M. I., A. M. Samoilenko, and S. I. Trofimchuk. “The Theory of the Numerical-Analytic Method: Achievements and New Trends of Development. VII”. Ukrains’kyi Matematychnyi Zhurnal 51, no. 9 (September 25, 1999): 1244–1261. Accessed May 17, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4720.