@article{DE_1991_27_8_a14,
     author = {A. O. Oganesyan},
     title = {The {Huygens} principle for a class of hyperbolic equations with variable coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1402--1409},
     publisher = {mathdoc},
     volume = {27},
     number = {8},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1991_27_8_a14/}
}