TY  - JOUR
AU  - Dinca, George
AU  - Goeleven, Daniel
AU  - Paşca, Daniel
TI  - Duality mapping and the existence of periodic solutions for non-autonomous second order systems.
JO  - Portugaliae mathematica
PY  - 2006
SP  - 47
EP  - 68
VL  - 63
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/PORMA_2006__63_1_52975/
LA  - en
ID  - PORMA_2006__63_1_52975
ER  -