@article{BUMI_2007_8_10B_1_a0,
     author = {Delort, Jean-Marc},
     title = {Normal {Forms} and {Long} {Time} {Existence} for {Semi-Linear} {Klein-Gordon} {Equations}},
     journal = {Bollettino della Unione matematica italiana},
     pages = {1--23},
     publisher = {mathdoc},
     volume = {Ser. 8, 10B},
     number = {1},
     year = {2007},
     zbl = {1178.35310},
     mrnumber = {2310955},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/BUMI_2007_8_10B_1_a0/}
}