TY  - JOUR
AU  - A. P. Vorob'ev
TI  - Sufficiency conditions for isochronism of canonical systems of two differential equations
JO  - Differencialʹnye uravneniâ
PY  - 1965
SP  - 582
EP  - 584
VL  - 1
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1965_1_5_a1/
LA  - ru
ID  - DE_1965_1_5_a1
ER  -