1. Horn, B.K.P.: Robot Vision. MIT Press, Cambridge (2001)
2. Horn, B.K.P., Brooks, M.J.: Shape from Shading. MIT Press, Cambridge (1989)
3. Deift, P., Sylvester, J.: Some remarks on shape-from-shading in computer vision. J. Math. Anal. Appl. 1(84), 235–248 (1991)
4. Oliensis, J.: Uniqueness in shape from shading. Int. J. Comput. Vis. 6(2), 75–104 (1991)
5. Brooks, M.J., Chojnacki, W., Kozera, R.: Shading without shape. Quart. Appl. Math. 50(1), 27–38 (1992)