1. Goldreich, P., and Julian, W. H., Astrophys. J., 157, 869 (1969).
2. Parker, E. N., Interplanetary Dynamical Processes, 137 (Interscience, New York, 1963).
3. Pierce, J. R., Theory and Design of Electron Beams (Van Nostrand, Princeton, 1954).
4. Shklovsky, I. S., Cosmic Radio Waves, 192 (Harvard University Press, Cambridge, 1960).
5. Erber, T., Rev. Mod. Phys., 38, 626 (1966).