@article{DAN_1979_249_2_a7,
     author = {V. V. Kucherenko and Yu. V. Osipov},
     title = {Asymptotic solutions of a hyperbolic equation with characteristics of variable multiplicity},
     journal = {Doklady Akademii Nauk},
     pages = {289--293},
     publisher = {mathdoc},
     volume = {249},
     number = {2},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1979_249_2_a7/}
}