1. Baldwin, D. E., Bernstein, I. B., and Weenink, M. P. H.: 1969, in A. Simon and W. B. Thompson (eds.),Advances in Plasma Physics, Vol. 3, 1, N. Y.
2. Dory, R. A., Guest, G. E., and Harris, E. G.: 1965,Phys. Rev. Letters 14, 131.
3. Fredricks, R. W.: 1971,J. Geophys. Res. 76, 5344.
4. Gruber, S., Klein, M. W., and Auer, P. L.: 1965,Phys. Fluids 8, 1504.
5. Karpman, V. I., Alekhin, Ju. K., Borisov, N. D., and Rjabova, N. A.: 1973,Phys. Letters (in press).