@article{AA_1994_6_5_a2,
     author = {V. M. Babich and A. A. Klimova},
     title = {A~hyperbolic equation with a~large parameter, with low-order terms, and wave hierarchy},
     journal = {Algebra i analiz},
     pages = {126--171},
     publisher = {mathdoc},
     volume = {6},
     number = {5},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1994_6_5_a2/}
}