@article{EJDE_2014__2014__a12,
     author = {Zhang,  Dan and Wu,  Qinghua and Dai,  Binxiang},
     title = {Existence and multiplicity of periodic solutions generated by impulses for second-order {Hamiltonian} system},
     journal = {Electronic journal of differential equations},
     year = {2014},
     volume = {2014},
     zbl = {1304.34077},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2014__2014__a12/}
}