1. M. Born and E. Wolf,Principles of Optics, Pergamon Press, Oxford, Sixth Edition, 1980.
2. J.D. Gaskill,Linear Systems, Fourier Transforms, and Optics, John Wiley and Sons, New York, 1978.
3. J.W. Goodman,Introduction to Fourier Optics, McGraw-Hill, Inc., 1968.
4. P. Grossman, “Depth from Focus,”Pattern Recognition Letters 5, pp. 63–69, Jan. 1987.
5. B.K.P. Horn, “Focusing,” Artificial Intelligence Memo No. 160, MIT, 1968.