@article{JMPA_1868_2_13__1_0,
     author = {Liouville, J.},
     title = {Extrait d'une {Lettre} adress\'ee \`a {M.} {Besge}},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {1--4},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 13},
     year = {1868},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1868_2_13__1_0/}
}