TY  - JOUR
AU  - M. A. Krasnosel'skii
AU  - V. V. Strygin
TI  - Some criteria for the existence of periodic solutions of ordinary differential equations
JO  - Doklady Akademii Nauk
PY  - 1964
SP  - 1022
EP  - 1024
VL  - 156
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1964_156_5_a8/
LA  - ru
ID  - DAN_1964_156_5_a8
ER  -