@article{DCG_1993__9_2_131248,
     author = {K. Kedem and M. Sharir and D.P. Huttenlocher},
     title = {The {Upper} {Envelope} of {Voronoi} {Surfaces} and {Its} {Applications.}},
     journal = {Discrete & computational geometry},
     pages = {267--292},
     publisher = {mathdoc},
     volume = {9},
     number = {2},
     year = {1993},
     zbl = {0770.68111},
     url = {http://geodesic.mathdoc.fr/item/DCG_1993__9_2_131248/}
}