@misc{ELMA_1969__24_140914,
     title = {Aufgaben.},
     journal = {Elemente der Mathematik},
     pages = {17--19},
     publisher = {mathdoc},
     volume = {24},
     year = {1969},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1969__24_140914/}
}