@article{JMPA_1866_2_11__39_0,
     author = {Liouville, J.},
     title = {Sur les deux formes $x^2+2y^2+2yz+2z^2+15t^2$, $2x^2+2xy+3y^2+3z^2+3t^2$},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {39--40},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 11},
     year = {1866},
     language = {fr},
     url = {http://archive.numdam.org/item/JMPA_1866_2_11__39_0/}
}