TY  - JOUR
AU  - A. E. Rudenok
TI  - Strong isochrony of the center. Periods of limit cycles of the Lienard system
JO  - Differencialʹnye uravneniâ
PY  - 1975
SP  - 811
EP  - 819
VL  - 11
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1975_11_5_a4/
LA  - ru
ID  - DE_1975_11_5_a4
ER  -