1. R.L. Gregory, Eye and Brain: The Psychology of Seeing, World University Library, Third Impression, 1967.
2. R.L. Gregory, The Intelligent Eye, McGraw-Hill, 1970.
3. T.N. Cornsweet, Visual Perception, Academic Press, 1970.
4. H. Davson, editor, The Eye, four volumes, Academic, 1969.
5. G.A. Fry, “The Eye and Vision”, Chapter 1 of Volume 2 of Applied Optics and Optical Engineering, R. Kingslake, editor, Academic, 1965.