1. Whitted, T., An improved illumination model for shaded display, Communications of the ACM 23(1980)6, 343–349.
2. Appel, A.A., Some techniques for shading machine renderings of solids, SJCC 1968, AFIPS Conf. Proc. Vol. 32(1968), 37–45.
3. Cook, R.L., Porter, T., Carpenter, L., Distributed ray tracing, Computer Graphics 18(1984)3, 137–145. Siggraph84.
4. Sutherland, I.E., Sproull, R.F., Schumacker, R.A., A characterization of ten hidden-surface algorithms, ACM Computing Surveys 6(1974)1, 1–55.
5. Potmesil, M. Generating three-dimensional surface models of solid objects from multiple projections. IPL-TR-033, Image Processing Lab. Rensselaer Polytechnic Institute, New York, Oct 1982.