@article{CTGDC_1980__21_4_347_0,
     author = {Ehresmann, Andr\'ee Charles},
     title = {In introduction to the {\textquotedblleft}3e colloque sur les cat\'egories, d\'edi\'e \`a {Charles} {Ehresmann{\textquotedblright}}},
     journal = {Cahiers de topologie et g\'eom\'etrie diff\'erentielle},
     pages = {347--352},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {21},
     number = {4},
     year = {1980},
     mrnumber = {606380},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1980__21_4_347_0/}
}