@article{DE_1977_13_8_a7,
     author = {T. Sh. Kal'menov},
     title = {The spectrum of the {Tricomi} problem for the {Lavrent'ev{\textendash}Bicadze} equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1418--1425},
     year = {1977},
     volume = {13},
     number = {8},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_8_a7/}
}