TY  - JOUR
AU  - I. M. Vul'pe
TI  - The determination of periodic solutions of nonlinear systems by the averaging method
JO  - Differencialʹnye uravneniâ
PY  - 1978
SP  - 1558
EP  - 1565
VL  - 14
IS  - 9
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1978_14_9_a2/
LA  - ru
ID  - DE_1978_14_9_a2
ER  -