1. Bumba, V. and Howard, R.: 1965, Astrophys. J. 141, 1502.
2. Davis, J. R. and Leverett: 1966, in The Solar Wind (ed. by R. J. Mackin Jr. and M. Neugebauer), Pergamon Press, p. 147.
3. Fan, C. Y., Pick, M., Pyle, R., Simpson, J. A., and Smith, D. R.: 1968, J. Geophys. Res. 73, 5.
4. Firor, J.: 1959, Paris Symposium on Radioastronomy, R. N. Bracewell (ed.), Stanford University Press, Stanford, p. 136.
5. Kakinuma, T. and Swarup, G.: 1962, Astrophys. J. 136, 975.