@article{JMPA_1866_2_11__211_0,
     author = {Liouville, J.},
     title = {Sur la forme $x^2+3y^2+az^2+3at^2$},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {211--216},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 11},
     year = {1866},
     language = {fr},
     url = {http://archive.numdam.org/item/JMPA_1866_2_11__211_0/}
}