@article{10_1007_s10492_013_0002_x,
     author = {Zhang, Liang and Tang, X. H.},
     title = {Periodic solutions for some nonautonomous $p(t)${-Laplacian} {Hamiltonian} systems},
     journal = {Applications of Mathematics},
     pages = {39--61},
     publisher = {mathdoc},
     volume = {58},
     number = {1},
     year = {2013},
     doi = {10.1007/s10492-013-0002-x},
     mrnumber = {3022768},
     zbl = {1274.34129},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10492-013-0002-x/}
}