TY  - JOUR
AU  - L. A. Cherkas
TI  - Methods for estimating the number of limit cycles of autonomous systems
JO  - Differencialʹnye uravneniâ
PY  - 1977
SP  - 779
EP  - 802
VL  - 13
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1977_13_5_a0/
LA  - ru
ID  - DE_1977_13_5_a0
ER  -