@article{EJDE_2013__2013__a159,
     author = {Torres,  Cesar},
     title = {Existence of solutions for fractional {Hamiltonian} systems},
     journal = {Electronic journal of differential equations},
     year = {2013},
     volume = {2013},
     zbl = {1295.34012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2013__2013__a159/}
}