@article{ELMA_1962__17_140737,
     author = {J. Schopp},
     title = {Versch\"arfung eines {Kreisabdeckungssatzes.}},
     journal = {Elemente der Mathematik},
     pages = {12--14},
     publisher = {mathdoc},
     volume = {17},
     year = {1962},
     zbl = {0098.35704},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1962__17_140737/}
}