@article{VSGTU_2015_19_4_a8,
     author = {I. N. Rodionova and V. M. Dolgopolov},
     title = {A similar for $\Delta_1$ problem for the second-order hyperbolic equation in the {3D} {Euclidean} space},
     journal = {Journal of Samara State Technical University, Ser. Physical and Mathematical Sciences},
     pages = {697--709},
     publisher = {mathdoc},
     volume = {19},
     number = {4},
     year = {2015},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VSGTU_2015_19_4_a8/}
}