TY  - JOUR
AU  - E. A. Livshitz
TI  - On duality principles for the problem of periodic solutions of higher order differential equations
JO  - Doklady Akademii Nauk
PY  - 1965
SP  - 277
EP  - 280
VL  - 165
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1965_165_2_a7/
LA  - ru
ID  - DAN_1965_165_2_a7
ER  -