References
- Mandel , L. and Wolf , E. 1961 . J. opt. Soc. Am. , 51 : 815 – 815 .
- Mandel , L. and Wolf , E. 1981 . Optics Commun. , 36 : 247 – 247 .
- Carter , W.H. 1983 . The Optical Society of America Handbook of Optics , Edited by: Bass , M. New York : McGraw-Hill .