@article{JMPA_1921_8_4__343_0,
     author = {Nagel, Trygve},
     title = {G\'en\'eralisation d'un th\'eor\`eme de {Tchebycheff}},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {343--356},
     publisher = {Gauthier-Villars},
     volume = {8e s{\'e}rie, 4},
     year = {1921},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1921_8_4__343_0/}
}