@article{10_4064_fm_54_2_211_228,
     author = {Ch. Ehresmann},
     title = {Sous-structures et cat\'egories ordonn\'ees},
     journal = {Fundamenta Mathematicae},
     pages = {211--228},
     year = {1964},
     volume = {54},
     number = {2},
     doi = {10.4064/fm-54-2-211-228},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-54-2-211-228/}
}