@article{CMFD_2019_65_2_a0,
     author = {E. L. Shishkina},
     title = {General {Euler{\textendash}Poisson{\textendash}Darboux} equation and hyperbolic $B$-potentials},
     journal = {Contemporary Mathematics. Fundamental Directions},
     pages = {157--338},
     year = {2019},
     volume = {65},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/CMFD_2019_65_2_a0/}
}