TY  - JOUR
AU  - M. A. Chahkiev
TI  - Linear differential operators with real spectrum, and optimal quadrature formulas
JO  - Izvestiya. Mathematics 
PY  - 1985
SP  - 391
EP  - 417
VL  - 25
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1985_25_2_a6/
LA  - en
ID  - IM2_1985_25_2_a6
ER  -