@article{ASENS_1899_3_16__239_0,
     author = {Cartan, \'Elie},
     title = {Sur certaines expressions diff\'erentielles et le probl\`eme de {Pfaff}},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {239--332},
     publisher = {Elsevier},
     volume = {3e s{\'e}rie, 16},
     year = {1899},
     doi = {10.24033/asens.467},
     language = {fr},
     url = {http://archive.numdam.org/articles/10.24033/asens.467/}
}