1. Graham, C. H., Vision and Visual Perception, John Wiley &Sons, London, 1966.
2. Hestenes, D. and G. Sobczyk, Clifford Algebra to Geometric Calculus,D. Reidel, Dordrecht, 1984.
3. Horn, B. K. P. and M. J. Brooks, Shape from Shading, The M.I.T. Press, Cambridge, MA, 1989.
4. Jaynes, E. T., Prior probabilities, IEEE
SSS-4 (1968), 227–241.
5. Koenderink, J. J., The structure of images, Biological Cybernetics
50 (1984), 363–370.