@article{DE_1971_7_1_a5,
     author = {A. M. Nakhushev},
     title = {The {Darboux} problem for degenerate hyperbolic equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {49--56},
     publisher = {mathdoc},
     volume = {7},
     number = {1},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_1_a5/}
}