@article{SHC_1949-1950__2__A3_0,
     author = {Cartan, H.},
     title = {Probl\`emes d'homotopie et de prolongement : th\'eorie des obstructions},
     journal = {S\'eminaire Henri Cartan},
     note = {talk:3},
     pages = {1--10},
     publisher = {Secr\'etariat math\'ematique},
     volume = {2},
     year = {1949-1950},
     language = {fr},
     url = {http://www.numdam.org/item/SHC_1949-1950__2__A3_0/}
}