@incollection{SB_1973-1974__16__69_0,
     author = {Koszul, Jean-Louis},
     title = {Travaux de {S.} {S.} {Chern} et {J.} {Simons} sur les classes caract\'eristiques},
     booktitle = {S\'eminaire Bourbaki. : vol. 1973/74, expos\'es 436-452},
     series = {S\'eminaire Bourbaki},
     note = {talk:440},
     pages = {69--88},
     publisher = {Springer-Verlag},
     number = {16},
     year = {1975},
     mrnumber = {425979},
     zbl = {0305.57020},
     language = {fr},
     url = {http://archive.numdam.org/item/SB_1973-1974__16__69_0/}
}