@article{ELMA_1956__11_140641,
     author = {H. Hadwiger},
     title = {Ungel\"oste {Probleme.}},
     journal = {Elemente der Mathematik},
     pages = {36--37},
     publisher = {mathdoc},
     volume = {11},
     year = {1956},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1956__11_140641/}
}