@article{JMPA_1846_1_11__21_0,
     author = {Liouville, J.},
     title = {D\'emonstration g\'eom\'etrique relative \`a l'\'equation des lignes g\'eod\'esiques sur les surfaces du second degr\'e},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {21--24},
     publisher = {Gauthier-Villars},
     volume = {1e s{\'e}rie, 11},
     year = {1846},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1846_1_11__21_0/}
}