TY  - JOUR
AU  - V. B. Lidskii
TI  - A theorem on the spectra of a perturbed differential operator
JO  - Doklady Akademii Nauk
PY  - 1957
SP  - 994
EP  - 997
VL  - 112
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1957_112_6_a3/
LA  - ru
ID  - DAN_1957_112_6_a3
ER  -