TY  - JOUR
AU  - V. K. Akhramenko
AU  - A. P. Sadovskii
TI  - Necessary conditions for a center for a differential system with a complex singular point
JO  - Differencialʹnye uravneniâ
PY  - 1988
SP  - 2032
EP  - 2042
VL  - 24
IS  - 12
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1988_24_12_a1/
LA  - ru
ID  - DE_1988_24_12_a1
ER  -