Ronto, M. I., A. M. Samoilenko, and S. I. Trofimchuk. “The Theory of the Numerical-Analytic Method: Achievements and New Trends of Development. III”. Ukrains’kyi Matematychnyi Zhurnal 50, no. 7 (July 25, 1998): 960–979. Accessed December 15, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4876.