Esther Moet Christian Knauer Marc J. van Kreveld Visibility Maps of Segments and Triangles in 3D. 20-29 2006 conf/iccsa/2006-1 ICCSA (1) http://dx.doi.org/10.1007/11751540_3 db/conf/iccsa/iccsa2006-1.html#MoetKK06