@article{BSMF_1931__59__40_0,
     author = {Feraud, Lucien},
     title = {Formes de {Pfaff} et syst\`emes lagrangiens},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {40--45},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {59},
     year = {1931},
     doi = {10.24033/bsmf.1171},
     zbl = {0002.20903},
     language = {fr},
     url = {http://www.numdam.org/articles/10.24033/bsmf.1171/}
}