@article{GDZPPN000366250,
title = {An Invariant Property of Balls in Arrangements of Hyperplanes.},
journal = {Discrete \& computational geometry},
volume = {10},
year = {1993},
pages = {421-426},
zbl = {0788.52013},
url = {http://dml.mathdoc.fr/item/GDZPPN000366250}
}
Sharir, M.; Aronov, B.; Naiman, D.Q.; Pack, J. An Invariant Property of Balls in Arrangements of Hyperplanes.. Discrete & computational geometry, Tome 10 (1993) pp. 421-426. http://gdmltest.u-ga.fr/item/GDZPPN000366250/