@article{DE_1972_8_1_a1,
     author = {V. N. Vragov},
     title = {The {Goursat} and {Darboux} problems for a certain class of hyperbolic equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {7--16},
     publisher = {mathdoc},
     volume = {8},
     number = {1},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1972_8_1_a1/}
}