@article{JMPA_1867_2_12__47_0,
     author = {Liouville, J.},
     title = {Sur la forme \`a cinq ind\'etermin\'ees $x_1x_2+x_2x_3+x_3x_4+x_4x_5$},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {47--48},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 12},
     year = {1867},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1867_2_12__47_0/}
}