@article{DE_1989_25_3_a18,
     author = {L. A. Zhelezovskaya and S. E. Zhelezovsky and V. Ph. Kirichenko and V. A. Krys'ko},
     title = {Symmetrization of an operator of a boundary value problem for a hyperbolic equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {523--525},
     publisher = {mathdoc},
     volume = {25},
     number = {3},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_3_a18/}
}