TY  - JOUR
AU  - V. A. Il'in
TI  - An estimate for the difference of the Riesz means of two spectral expansions for a function in the class~$L_2$
JO  - Differencialʹnye uravneniâ
PY  - 1988
SP  - 852
EP  - 863
VL  - 24
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1988_24_5_a14/
LA  - ru
ID  - DE_1988_24_5_a14
ER  -