TY  - JOUR
AU  - N. V. Pyzhkova
AU  - A. P. Sadovskii
TI  - A method for solving the problem of isochronism of the center
JO  - Differencialʹnye uravneniâ
PY  - 1980
SP  - 1893
EP  - 1895
VL  - 16
IS  - 10
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1980_16_10_a21/
LA  - ru
ID  - DE_1980_16_10_a21
ER  -