@article{JMPA_1862_2_7__5_0,
     author = {Liouville, J.},
     title = {Sur la forme $\mathrm{X}^2+8\left(\mathrm{Y}^2+\mathrm{Z}^2+\mathrm{T}^2\right)$},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {5--8},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 7},
     year = {1862},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1862_2_7__5_0/}
}