TY  - JOUR
AU  - Karl-Peter Hadeler
TI  - Estimates for the spectrum of normal operators
JO  - Doklady Akademii Nauk
PY  - 1964
SP  - 284
EP  - 287
VL  - 157
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1964_157_2_a12/
LA  - ru
ID  - DAN_1964_157_2_a12
ER  -