1. Millodot, M.Dictionary of Optometry and Visual Science7th ed.; Edinburgh, Butterworth-Heinemann-Elsevier, 2009; p 216.
2. Hofstetter, H.W; Griffin, J.R.; Berman, M.S.; Everson, R.W.Dictionary of Visual Science and Related Clinical Terms5th ed.; Butterworth-Heinemann, Boston, MA, 2000; p 313.
3. Rabbetts, R.B.Bennett & Rabbetts’ Clinical Visual Optics4th ed.; Butterworth-Heinemann, Edinburgh, 2007; p 262.
4. ABCD law for partially coherent Gaussian light, propagating through first-order optical systems