@incollection{SB_1982-1983__25__105_0,
     author = {Berestycki, Henri},
     title = {Solutions p\'eriodiques de syst\`emes hamiltoniens},
     booktitle = {S\'eminaire Bourbaki : volume 1982/83, expos\'es 597-614},
     series = {Ast\'erisque},
     note = {talk:603},
     pages = {105--128},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {105-106},
     year = {1983},
     mrnumber = {728984},
     zbl = {0526.58016},
     language = {fr},
     url = {http://archive.numdam.org/item/SB_1982-1983__25__105_0/}
}