@article{ELMA_1965__20_140798,
     author = {O. Bottema},
     title = {Ein {Schliessungssatz} f\"ur zwei {Kreise.}},
     journal = {Elemente der Mathematik},
     pages = {1--7},
     publisher = {mathdoc},
     volume = {20},
     year = {1965},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1965__20_140798/}
}