AldashevS. A. (2010) “Existence of eigenfunctions of the Tricomi spectral problem for some classes of multidimensional mixed hyperbolic–parabolic equations”, Ukrains’kyi Matematychnyi Zhurnal, 62(6), pp. 723 -. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2904 (Accessed: 22December2024).