@article{ELMA_1968__23_140887,
     author = {E. Schr\"oder},
     title = {Eigenschaften gewisser {Scheitelkreise} einer {Ellipse} bez\"uglich ihrer {Brennpunkte.}},
     journal = {Elemente der Mathematik},
     pages = {63--64},
     publisher = {mathdoc},
     volume = {23},
     year = {1968},
     zbl = {0153.50702},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1968__23_140887/}
}