@article{JDM_1915__24_145439,
     author = {Wilhelm Blaschke},
     title = {Kreis und {Kugel.}},
     journal = {Jahresbericht der Deutschen Mathematiker-Vereinigung},
     pages = {195--207},
     publisher = {mathdoc},
     volume = {24},
     year = {1915},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/JDM_1915__24_145439/}
}