@article{JMPA_1856_2_1__210_0,
     author = {Lejeune-Dirichlet},
     title = {Sur l'\'equation $t^2+u^2+v^2+w^2=4^m$},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {210--214},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 1},
     year = {1856},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1856_2_1__210_0/}
}