@article{GDZPPN002077027,
title = {Ungel\"oste Probleme.},
journal = {Elemente der Mathematik},
volume = {24},
year = {1969},
pages = {126-128},
url = {http://dml.mathdoc.fr/item/GDZPPN002077027}
}
Hadwiger, H. Ungelöste Probleme.. Elemente der Mathematik, Tome 24 (1969) pp. 126-128. http://gdmltest.u-ga.fr/item/GDZPPN002077027/