TY  - JOUR
AU  - V. D. Budaev
TI  - Criteria for the Bessel property and the Riesz basis property of systems of root functions of differential operators. I
JO  - Differencialʹnye uravneniâ
PY  - 1991
SP  - 2033
EP  - 2044
VL  - 27
IS  - 12
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1991_27_12_a1/
LA  - ru
ID  - DE_1991_27_12_a1
ER  -