@article{ELMA_1963__18_140772, author = {H. Hadwiger}, title = {Ungel\"oste {Probleme.}}, journal = {Elemente der Mathematik}, pages = {85--85}, year = {1963}, volume = {18}, url = {http://geodesic.mathdoc.fr/item/ELMA_1963__18_140772/} }