TY  - JOUR
AU  - I. G. Kozubovskaya
TI  - Periodic solutions of some systems of nonlinear differential equations
JO  - Differencialʹnye uravneniâ
PY  - 1991
SP  - 705
EP  - 707
VL  - 27
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1991_27_4_a20/
LA  - ru
ID  - DE_1991_27_4_a20
ER  -