@incollection{AST_1977__50__R1_0,
     author = {AST},
     title = {},
     booktitle = {Syst\`emes dynamiques II - Varsovie},
     series = {Ast\'erisque},
     pages = {i--x},
     year = {1977},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {50},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AST_1977__50__R1_0/}
}