Kolos, I.V., and M.V. Kolos. “Approximate Solution of a Generalized Boundary Value Problem for Hyperbolic-Type Equations With Degeneracy”. Numerical Methods and Programming (Vychislitel’nye Metody i Programmirovanie) 6, no. 6 (November 7, 2005): 283–289. Accessed April 28, 2024. https://en.num-meth.ru/index.php/journal/article/view/171.