@article{DE_1977_13_12_a21,
     author = {M. Otelbaev},
     title = {Letter to the editors: {{\textquotedblleft}A} criterion for discreteness of the spectrum for a degenerate operator, and certain imbedding theorems{\textquotedblright} {(Differencial'nye} {Uravnenija} 13 (1977), no.~1, 111{\textendash}120)},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2288},
     year = {1977},
     volume = {13},
     number = {12},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_12_a21/}
}