@article{ELMA_1964__19_140788,
     author = {H. Schaal},
     title = {Euklidische und pseudoeuklidische {S\"atze} \"uber {Kreis} und gleichseitige {Hyperbel.}},
     journal = {Elemente der Mathematik},
     pages = {53--56},
     publisher = {mathdoc},
     volume = {19},
     year = {1964},
     zbl = {0121.15801},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1964__19_140788/}
}