@article{DE_2006_42_1_a7,
     author = {D. V. Kornienko},
     title = {On a spectral problem for two hyperbolic systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {91--100},
     year = {2006},
     volume = {42},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2006_42_1_a7/}
}