TY  - JOUR
AU  - G. S. Rychkov
TI  - The uniqueness of the limit cycle of the system $\dot y=-g(x)$, $\dot x=-f(x)$
JO  - Differencialʹnye uravneniâ
PY  - 1969
SP  - 563
EP  - 564
VL  - 5
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1969_5_3_a17/
LA  - ru
ID  - DE_1969_5_3_a17
ER  -