TY  - JOUR
AU  - V. V. Amel'kin
TI  - The periodic solutions of a certain nonautonomous system
JO  - Differencialʹnye uravneniâ
PY  - 1969
SP  - 2085
EP  - 2086
VL  - 5
IS  - 11
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1969_5_11_a13/
LA  - ru
ID  - DE_1969_5_11_a13
ER  -