TY  - JOUR
AU  - L. A. Cherkas
AU  - A. A. Grin'
TI  - A second-degree polynomial Dulac function for a cubic system on the plane
JO  - Differencialʹnye uravneniâ
PY  - 1997
SP  - 1435
EP  - 1436
VL  - 33
IS  - 10
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1997_33_10_a19/
LA  - ru
ID  - DE_1997_33_10_a19
ER  -