Gadjiev, T., M. Kerimova, and G. Gasanova. “Solvability of a Boundary-Value Problem for Degenerate Equations”. Ukrains’kyi Matematychnyi Zhurnal 72, no. 4 (March 28, 2020): 435-451. Accessed May 4, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/6000.