@misc{ELMA_1966__21_140827,
     title = {Ungel\"oste {Probleme.}},
     journal = {Elemente der Mathematik},
     pages = {90--90},
     publisher = {mathdoc},
     volume = {21},
     year = {1966},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1966__21_140827/}
}