@article{AIHPC_2017__34_5_1255_0,
     author = {Lu, Nan},
     title = {Small amplitude periodic solutions of {Klein{\textendash}Gordon} equations},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {1255--1272},
     publisher = {Elsevier},
     volume = {34},
     number = {5},
     year = {2017},
     doi = {10.1016/j.anihpc.2016.10.002},
     mrnumber = {3742523},
     zbl = {1388.35006},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.anihpc.2016.10.002/}
}