@article{GDZPPN002075172,
title = {Ungel\"oste Probleme.},
journal = {Elemente der Mathematik},
volume = {18},
year = {1963},
pages = {29-31},
url = {http://dml.mathdoc.fr/item/GDZPPN002075172}
}
Hadwiger, H. Ungelöste Probleme.. Elemente der Mathematik, Tome 18 (1963) pp. 29-31. http://gdmltest.u-ga.fr/item/GDZPPN002075172/