@article{DE_1984_20_1_a9,
     author = {E. I. Moiseev},
     title = {Approximation of the classical solution of the {Darboux} problem by smooth solutions},
     journal = {Differencialʹnye uravneni\^a},
     pages = {73--87},
     publisher = {mathdoc},
     volume = {20},
     number = {1},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_1_a9/}
}