Aaron Knoll Younis Hijazi Andrew Kensler Mathias Schott Charles D. Hansen Hans Hagen Fast Ray Tracing of Arbitrary Implicit Surfaces with Interval and Affine Arithmetic. 26-40 2009 28 Comput. Graph. Forum 1 http://dx.doi.org/10.1111/j.1467-8659.2008.01189.x db/journals/cgf/cgf28.html#KnollHKSHH09