@article{MAN_1921__83_158864,
     author = {A. Schur},
     title = {\"Uber die {Schwarzsche} {Extremaleigenschaft} des {Kreises} unter den {Kurven} konstanter {Kr\"ummung}},
     journal = {Mathematische Annalen},
     pages = {143--148},
     publisher = {mathdoc},
     volume = {83},
     year = {1921},
     zbl = {48.0806.02},
     url = {http://geodesic.mathdoc.fr/item/MAN_1921__83_158864/}
}