TY  - JOUR
AU  - V. I. Mironenko
TI  - Simple systems and periodic solutions of differential equations
JO  - Differencialʹnye uravneniâ
PY  - 1989
SP  - 2109
EP  - 2114
VL  - 25
IS  - 12
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1989_25_12_a9/
LA  - ru
ID  - DE_1989_25_12_a9
ER  -