@article{DE_1975_11_1_a23,
     author = {S. V. Zubarev},
     title = {The ill-posedness of the multidimensional analogue of the {Darboux} problem for a hyperbolic equation with degeneracy},
     journal = {Differencialʹnye uravneni\^a},
     pages = {188--191},
     publisher = {mathdoc},
     volume = {11},
     number = {1},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_1_a23/}
}