1. K. J. Gringans, Space Res., 2: 539 (1962)
2. M. Nengetaner and C. W. Snyder, Space Res., 138:1095 (1962).
3. J. H. Chisholm and J. C. James, Astrophys. J., 140:377 (1964).
4. E.N. Parker, Interplanetary Dynamical Processes (Interscience Monographs and Texts in Physics and Astronomy, Vol. 8), New York (1963).
5. M. V. Konyukov, in: Wideband Cruciform Radio Telescope Research (D. V. Skobel’tsyn, ed.), Consultants Bureau, New York (1969), p. 115.