1. Jahoda F. C., Sawyer G. A.: Optical Refractivity of Plasmas. Methods of Experimental Physics, Vol. IX, Part B, Academic Press, New York-London, 1971, p. 1.
2. Vasilyev L. A.: Tenevyye Metody, Nauka, Moskva, 1968, p. 37.
3. Kravárik J. et al.: Čes. Čas. Fyz. A31 (1981) 360.
4. Kravárik J. et al.: Czech. J. Phys. B32 (1982) 713.
5. Kravárik J. et al.: Acta Phys. Slovaca33 (1983) 209.