@article{NAM_1848_1_7__37_0,
     author = {Lebesgue},
     title = {R\'esolution en nombres entiers de l{\textquoteright}\'equation $x^2+y^2=z^2+t^2$},
     journal = {Nouvelles annales de math\'ematiques : journal des candidats aux \'ecoles polytechnique et normale},
     pages = {37--39},
     publisher = {Carilian-Goeury et Vor Dalmont},
     volume = {1e s{\'e}rie, 7},
     year = {1848},
     language = {fr},
     url = {http://www.numdam.org/item/NAM_1848_1_7__37_0/}
}