@article{MAN_1967__171_161567,
     author = {CH. EHRESMANN},
     title = {Structures {Quasi-Quotient.}},
     journal = {Mathematische Annalen},
     pages = {293--364},
     publisher = {mathdoc},
     volume = {171},
     year = {1967},
     zbl = {0248.18007},
     url = {http://geodesic.mathdoc.fr/item/MAN_1967__171_161567/}
}