TY  - JOUR
AU  - V. A. Pliss
TI  - The existence of periodic solutions of certain non-linear systems
JO  - Doklady Akademii Nauk
PY  - 1961
SP  - 1060
EP  - 1062
VL  - 137
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1961_137_5_a14/
LA  - ru
ID  - DAN_1961_137_5_a14
ER  -