TY  - JOUR
AU  - O. G. Parfenov
TI  - Estimates of the spectrum of some differential operators
JO  - Matematičeskie zametki
PY  - 1997
SP  - 634
EP  - 636
VL  - 61
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1997_61_4_a15/
LA  - ru
ID  - MZM_1997_61_4_a15
ER  -