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@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/} }
V. N. Vragov. The Goursat and Darboux problems for a certain class of hyperbolic equations. Differencialʹnye uravneniâ, Tome 8 (1972) no. 1, pp. 7-16. http://geodesic.mathdoc.fr/item/DE_1972_8_1_a1/