TY  - JOUR
AU  - L. A. Cherkas
AU  - V. A. Gaǐko
TI  - Bifurcations of limit cycles of a quadratic system with two singular points and two parameters that rotate the field
JO  - Differencialʹnye uravneniâ
PY  - 1987
SP  - 1544
EP  - 1553
VL  - 23
IS  - 9
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1987_23_9_a8/
LA  - ru
ID  - DE_1987_23_9_a8
ER  -