@article{SE_1960-1962__3__A5_0,
     author = {Ehresmann, C.},
     title = {\'Elargissements de cat\'egories},
     journal = {S\'eminaire de topologie et g\'eom\'etrie diff\'erentielle},
     note = {talk:4},
     pages = {25--73},
     publisher = {Secr\'etariat math\'ematique},
     volume = {3},
     year = {1960-1962},
     zbl = {0106.36302},
     language = {fr},
     url = {http://www.numdam.org/item/SE_1960-1962__3__A5_0/}
}