TY  - JOUR
AU  - D. S. Ushkho
TI  - On the coexistence of limit cycles and singular points of ``center'' type of cubic differential systems
JO  - Differencialʹnye uravneniâ
PY  - 1995
SP  - 173
EP  - 174
VL  - 31
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1995_31_1_a28/
LA  - ru
ID  - DE_1995_31_1_a28
ER  -