TY  - JOUR
AU  - E. D. Zhitelzeif
TI  - A test for the existence of a periodic solution of the Li\'enard equation
JO  - Differencialʹnye uravneniâ
PY  - 1970
SP  - 1127
EP  - 1130
VL  - 6
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1970_6_6_a20/
LA  - ru
ID  - DE_1970_6_6_a20
ER  -