TY  - JOUR
AU  - V. V. Amel'kin
AU  - Ching Zan Dang
TI  - Strong isochronism of the center of dynamical systems with second-degree polynomials
JO  - Differencialʹnye uravneniâ
PY  - 1993
SP  - 739
EP  - 743
VL  - 29
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1993_29_5_a0/
LA  - ru
ID  - DE_1993_29_5_a0
ER  -