1. Adeishvili, T. G., Gurevich, A. V., Lyakhov, S. B., Managadze, G. G., Milikh, G. M., and Shlyuger, I. S.: 1978,Soviet J. Plasma Phys. 4 (6), 721.
2. Banks, P. M.: 1977,J. Atmospheric Terrest. Phys. 39, 179.
3. Chakrabarti, A. K., and De, S. S.: 1982,Indian J. Radio Space Phys. 11, 236.
4. Chakravarti, A. K. and Ram, S.: 1974,Indian J. Radio Space Phys. 3, 9.
5. Chimonas, G., and Hines, C. O.: 1970,Planetary Space Sci. 18, 565.