Les groupes Ext s (A,B)
Séminaire A. Grothendieck, Tome 1 (1957) , Exposé no. 3, 14 p. 
@article{SG_1957__1__A3_0,
     author = {Cartier, Pierre},
     title = {Les groupes $\mathrm {Ext}^s (A,B)$},
     journal = {S\'eminaire A. Grothendieck},
     note = {talk:3},
     publisher = {Secr\'etariat math\'ematique},
     volume = {1},
     year = {1957},
     language = {fr},
     url = {www.numdam.org/item/SG_1957__1__A3_0/}
}
Cartier, Pierre. Les groupes $\mathrm {Ext}^s (A,B)$. Séminaire A. Grothendieck, Tome 1 (1957) , Exposé no. 3, 14 p. http://www.numdam.org/item/SG_1957__1__A3_0/