@article{MZ_1918__1_167449,
     author = {W., Blaschke},
     title = {Eine isoperimetrische {Eigenschaft} des {Kreises}},
     journal = {Mathematische Zeitschrift},
     pages = {52--57},
     year = {1918},
     volume = {1},
     zbl = {46.1109.02},
     url = {http://geodesic.mathdoc.fr/item/MZ_1918__1_167449/}
}