@article{SD_1967-1968__21_2_A9_0,
     author = {Ravel, Jacques},
     title = {Th\'eorie axiomatique de l'essentialit\'e},
     journal = {S\'eminaire Albert Ch\^atelet et Paul Dubreil},
     note = {talk:18},
     pages = {1--12},
     year = {1967-1968},
     publisher = {Secr\'etariat math\'ematique},
     volume = {21},
     number = {2},
     zbl = {0215.34103},
     language = {fr},
     url = {https://www.numdam.org/item/SD_1967-1968__21_2_A9_0/}
}