@article{GDZPPN002073684, title = {Ungel\"oste Probleme.}, journal = {Elemente der Mathematik}, volume = {10}, year = {1955}, pages = {42-43}, url = {http://dml.mathdoc.fr/item/GDZPPN002073684} }
Hadwiger, H. Ungelöste Probleme.. Elemente der Mathematik, Tome 10 (1955) pp. 42-43. http://gdmltest.u-ga.fr/item/GDZPPN002073684/