TY  - JOUR
AU  - A. Yu. Levin
TI  - A comparison principle for second-order differential equations
JO  - Doklady Akademii Nauk
PY  - 1960
SP  - 783
EP  - 786
VL  - 135
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1960_135_4_a4/
LA  - ru
ID  - DAN_1960_135_4_a4
ER  -