TY  - JOUR
AU  - L. A. Cherkas
TI  - Absence of limit cycles around a triple focus in a quadratic system in a plane
JO  - Differencialʹnye uravneniâ
PY  - 1986
SP  - 2015
EP  - 2017
VL  - 22
IS  - 11
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1986_22_11_a27/
LA  - ru
ID  - DE_1986_22_11_a27
ER  -