@article{GDZPPN00036343X,
title = {On the Number of Critical Free Contacts of a Convex Polygonal Object Moving in Two-Dimensional Polygonal Space.},
journal = {Discrete \& computational geometry},
volume = {2},
year = {1987},
pages = {255-270},
zbl = {0616.52009},
url = {http://dml.mathdoc.fr/item/GDZPPN00036343X}
}
Sharir, Micha; Leven, D. On the Number of Critical Free Contacts of a Convex Polygonal Object Moving in Two-Dimensional Polygonal Space.. Discrete & computational geometry, Tome 2 (1987) pp. 255-270. http://gdmltest.u-ga.fr/item/GDZPPN00036343X/