@misc{ELMA_1970__25_140973,
     title = {Aufgaben.},
     journal = {Elemente der Mathematik},
     pages = {63--67},
     publisher = {mathdoc},
     volume = {25},
     year = {1970},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1970__25_140973/}
}