@article{EJDE_2001__2001__a114,
     author = {Fei,  Guihua},
     title = {Nontrivial periodic solutions of asymptotically linear {Hamiltonian} systems},
     journal = {Electronic journal of differential equations},
     year = {2001},
     volume = {2001},
     zbl = {1001.37052},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2001__2001__a114/}
}