TY  - JOUR
AU  - N. I. Vulpe
AU  - I. V. Nikolaev
TI  - Topological classification of a quadratic system with a four-fold singular point
JO  - Differencialʹnye uravneniâ
PY  - 1993
SP  - 1669
EP  - 1674
VL  - 29
IS  - 10
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1993_29_10_a1/
LA  - ru
ID  - DE_1993_29_10_a1
ER  -