@article{DE_1983_19_1_a9,
     author = {T. Sh. Kal'menov},
     title = {Selfadjoint boundary value problems for the {Tricomi} equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {66--75},
     year = {1983},
     volume = {19},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1983_19_1_a9/}
}