@article{JMPA_1864_2_9__17_0, author = {Liouville, J.}, title = {Sur la forme $x^2+5\left(y^2+z^2+t^2\right)$}, journal = {Journal de Math\'ematiques Pures et Appliqu\'ees}, pages = {17--22}, publisher = {Gauthier-Villars}, volume = {2e s{\'e}rie, 9}, year = {1864}, language = {fr}, url = {http://www.numdam.org/item/JMPA_1864_2_9__17_0/} }