Christoph Burnikel Jochen Könemann Kurt Mehlhorn Stefan Näher Stefan Schirra Christian Uhrig Exact Geometric Computation in LEDA. C18-C19 1995 Symposium on Computational Geometry http://doi.acm.org/10.1145/220279.220330 db/conf/compgeom/compgeom95.html#BurnikelKMNSU95