TY  - JOUR
AU  - N. I. Vulpe
TI  - Coefficient conditions for the number and multiplicity of singular points of a quadratic differential system
JO  - Differencialʹnye uravneniâ
PY  - 1991
SP  - 572
EP  - 577
VL  - 27
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1991_27_4_a2/
LA  - ru
ID  - DE_1991_27_4_a2
ER  -