@article{DE_1973_9_1_a9,
     author = {V. V. Kovrizhkin},
     title = {Smoothness of the solutions of the generalized {Tricomi} problem},
     journal = {Differencialʹnye uravneni\^a},
     pages = {97--105},
     year = {1973},
     volume = {9},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_1_a9/}
}