@article{JMPA_1876_3_2__240_0,
     author = {Darboux},
     title = {Lettre \`a {M.} {Resal}},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {240--240},
     publisher = {Gauthier-Villars},
     volume = {3e s{\'e}rie, 2},
     year = {1876},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1876_3_2__240_0/}
}