TY  - JOUR
AU  - K. S. Sibirskii
TI  - On the number of limit cycles arising from a singular point of focus or center type
JO  - Doklady Akademii Nauk
PY  - 1965
SP  - 304
EP  - 307
VL  - 161
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1965_161_2_a12/
LA  - ru
ID  - DAN_1965_161_2_a12
ER  -