“ Well-Posedness of Dirichlet and Poincare Problems in a Cylindrical Domain for Degenerate Many Dimensional Hyperbolic Equations With Gellerstedt Operator”. Neliniini Kolyvannya 18, no. 1 (March 29, 2015): 10–19. Accessed April 12, 2026. https://nosc.imath.kiev.ua/index.php/nosc/article/view/765.