1. V. I. Aksenov, Izv. Vyssh. Uchebn. Zaved., Radiofiz.,18, No. 9, 1333 (1975).
2. V. I. Aksenov, V. A. Makarov, L. A. Zhekilin, Z. Ya. Kiseleva, I. V. Lishin, V. A. Makarov, and L. N. Mikhailov, Kosmich. Issled.,8, No. 4, 571 (1970).
3. V. I. Aksenov, L. A. Zhekulin, et al., Space Research,11, 1299 (1971).
4. V. I. Aksenov and M. V. Nazarova, in: Low-Frequency Signals and Waves in the Outer Ionosphere [in Russian], Apatity (1974), p. 91.
5. G. Nestorov, Geomagn. Aéron.,12, No. 1, 44 (1972).