@article{JMPA_1911_6_7__123_0,
     author = {Gau, E.},
     title = {Sur l'int\'egration des \'equations aux d\'eriv\'ees partielles du second ordre par la m\'ethode de {M.} {Darboux}},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {123--240},
     publisher = {Gauthier-Villars},
     volume = {6e s{\'e}rie, 7},
     year = {1911},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1911_6_7__123_0/}
}