AldashevS. A. (1994) “Well-posedness of many-dimensional Darboux problems for degenerating hyperbolic equations”, Ukrains’kyi Matematychnyi Zhurnal, 46(10), pp. 1304–1311. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5607 (Accessed: 27July2024).