1. R. H. Huddlestone and S. L. Leonard (Editors), Plasma Diagnostic Techniques, Academic Press, New York, 1965.
2. H. R. Griem and R. H. Lovberg (Editors), Methods of Experimental Physics: Plasma Physics, Part A, Academic Press, New York, 1970.
3. E. E. Salpeter, Physical Review, 120, 1528 (1960).
4. J. P. Dougherty and D. T. Farley, Proc. Royal Society (London), Ser. A, 259, 79 (1960).
5. R. J. Glauber, in Quantum Optics and Electronics (Edited by C. De Witt, A. Blandin and C. Cohen-Tannoudji), Gordon and Breach, New York, 1965.