@article{SE_1963__5__A3_0,
     author = {Ehresmann, Charles},
     title = {Cat\'egories structur\'ees {III.} {Quintettes} et applications covariantes},
     journal = {S\'eminaire Ehresmann. Topologie et g\'eom\'etrie diff\'erentielle},
     note = {talk:3},
     pages = {1--21},
     publisher = {Secr\'etariat math\'ematique},
     volume = {5},
     year = {1963},
     mrnumber = {191939},
     zbl = {0207.32502},
     language = {fr},
     url = {http://www.numdam.org/item/SE_1963__5__A3_0/}
}