1. Surkov, Yu. A., Moskaleva, L. P., Manvelyan, O. S. & Khariukova, V. P. Kosmich. Issled. XVIII(4), 623–631 (1980).
2. Surkov, Yu. A. et al. Nature 341, 595–598 (1989).
3. Sagdeev, R. Z. & Zakharov, A. Nature 341, 581–585 (1989).
4. Reedy, R. C. in Proc. 9th Lunar planet. Sci. Conf. 2961–2984 (Pergamon, Oxford, 1978).
5. Bielefeld, M. J., Reedy, R. C., Metzger, A. E., Trombka, J. I. & Arnold, J. A. in Proc. 7th Lunar Sci. Conf. 2661–2676 (Pergamon, Oxford, 1976).