Un théorème fondamental de Chern en géométrie riemannienne
Séminaire Bourbaki : année 1961/62, exposés 223-240, Séminaire Bourbaki no. 7  (1962), Talk no. 239, p. 273-284 
@incollection{SB_1961-1962__7__273_0,
     author = {Weil, Andr\'e},
     title = {Un th\'eor\`eme fondamental de Chern en g\'eom\'etrie riemannienne},
     booktitle = {S\'eminaire Bourbaki : ann\'ee 1961/62, expos\'es 223-240},
     author = {Collectif},
     series = {S\'eminaire Bourbaki},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {7},
     year = {1962},
     note = {talk:239},
     pages = {273-284},
     zbl = {0116.38801},
     mrnumber = {1611223},
     language = {fr},
     url = {http://www.numdam.org/item/SB_1961-1962__7__273_0}
}

Weil, André. Un théorème fondamental de Chern en géométrie riemannienne, in Séminaire Bourbaki : année 1961/62, exposés 223-240, Séminaire Bourbaki, no. 7 (1962), Talk no. 239, pp. 273-284. http://www.numdam.org/item/SB_1961-1962__7__273_0/

[1] Ambrose (W.) and Singer (I.M.). - A theorem on holonomy, Trans. Amer. math. Soc., t. 75, 1953, p. 428-443. | MR 63739 | Zbl 0052.18002

[2] Chern (S.S.). - On a generalization of Kähler geometry, Algebraic Geometry and Topology, a Symposium in honor of S. Lefschetz, p. 103-121.-Princeton, Princeton University Press, 1957 (Princeton mathematical Series, 18). | MR 87172 | Zbl 0078.14103