TY  - JOUR
AU  - Yu. K. Metlyaev
TI  - The use of operators that have certain properties in qualitative investigations of differential equations
JO  - Differencialʹnye uravneniâ
PY  - 1970
SP  - 1976
EP  - 1981
VL  - 6
IS  - 11
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1970_6_11_a5/
LA  - ru
ID  - DE_1970_6_11_a5
ER  -