@incollection{SB_1970-1971__13__167_0,
     author = {Godbillon, Claude},
     title = {Probl\`emes d'existence et d'homotopie dans les feuilletages},
     booktitle = {S\'eminaire Bourbaki : vol. 1970/71, expos\'es 382-399},
     series = {S\'eminaire Bourbaki},
     note = {talk:390},
     pages = {167--181},
     publisher = {Springer-Verlag},
     number = {13},
     year = {1971},
     mrnumber = {420654},
     zbl = {0228.57017},
     language = {fr},
     url = {http://archive.numdam.org/item/SB_1970-1971__13__167_0/}
}