@article{GDZPPN002073846, title = {Ungel\"oste Probleme.}, journal = {Elemente der Mathematik}, volume = {10}, year = {1955}, pages = {130-132}, url = {http://dml.mathdoc.fr/item/GDZPPN002073846} }
Hadwiger, H. Ungelöste Probleme.. Elemente der Mathematik, Tome 10 (1955) pp. 130-132. http://gdmltest.u-ga.fr/item/GDZPPN002073846/