@article{GDZPPN002074222,
title = {Ungel\"oste Probleme.},
journal = {Elemente der Mathematik},
volume = {13},
year = {1958},
pages = {13-14},
url = {http://dml.mathdoc.fr/item/GDZPPN002074222}
}
Hadwiger, H. Ungelöste Probleme.. Elemente der Mathematik, Tome 13 (1958) pp. 13-14. http://gdmltest.u-ga.fr/item/GDZPPN002074222/