TY  - JOUR
AU  - I. A. Pasynkova
TI  - The existence of a family of periodic solutions of a system of two second order differential equations
JO  - Differencialʹnye uravneniâ
PY  - 1969
SP  - 814
EP  - 823
VL  - 5
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1969_5_5_a2/
LA  - ru
ID  - DE_1969_5_5_a2
ER  -