Erin W. Chambers Éric Colin de Verdière Jeff Erickson Francis Lazarus Kim Whittlesey Splitting (complicated) surfaces is hard. 421-429 2006 conf/compgeom/2006 Symposium on Computational Geometry http://doi.acm.org/10.1145/1137856.1137918 db/conf/compgeom/compgeom2006.html#ChambersVELW06