Appleton, E. V., Studies of the F2 layer in the ionosphere, J. Atmos. Terr. Phys., 1, 106–113, 1950.
Besprosvanaya, A. S. and P. E. Kozina, Variations of the electron density in the F2-layer maximum in the solar activity cycle, Geomagn. Aeron., 28, 639–643, 1988 (in Russian).
Bilitza, D., International Reference Ionosphere 1990, National Space Science Data Center, NSSDC/WDC-A-R&S 90-22, Greenbelt, Maryland, 1990.
Bryunelli, B. E. and A. A. Namgaladze, Physics of the Ionosphere, 528 pp., Nauka, Moscow, 1988 (in Russian).
Dolezalek, H., Discussion of the fundamental problem of atmospheric electricity, Pure Appl. Geophys., 100, 8–43, 1972.
Kuznetsov, V. V., V. V. Plotkin, I. I. Nesterova, and M. S. Pozdeeva, Universal diurnal variation of F2-layer critical frequency, J. Geomag. Geoelectr., 42, 1237–1240, 1990.
Kuznetsov, V. V., V. V. Plotkin, I. I. Nesterova, and N. I. Izraileva, Universal diurnal variation of F2-layer critical frequency as charac-teristic of global ionospheric condition, J. Geomag. Geoelectr., 45, 1175–1179, 1993.
Michailov, A. V., S. D. Buldenkova, V. V. Michailov, and Ju. L. Terechin, Comparison of the solar activity indices for the modelling of foF2 median value, Geomagn. Aeron., 30, 113–120 1990a (in Russian).
Michailov, A. V., Ju. L. Terechin, and V. V. Michailov, Regional effective index of the solar activity for the prediction of the monthly median values of foF2, Geomagn. Aeron., 30, 624–636, 1990b (in Russian).
Paramonov, N. A., On the universal variation of the atmospheric electric potential gradient, Doklady AN USSR, 70, 37–38, 1950 (in Russian).
Paramonov, N. A., Determination of the global diurnal variation of the potential gradient of the electric field in the atmosphere and the vertical conduction current, National Service for Technical Information, Springfield, Virginia, 22151, U.S.A., N JRPA 55331, Meteorology and Hydrology, No. 12, 89–94, 1972.
Parkinson, W. C. and O. W. Torreson, The diurnal variation of the electric potential of the atmosphere over the oceans, UGGI (Sect. Terr. Magn. Elec.) Bull. No. 8, 340–341, 1931.
Plotkin, V. V., I. I. Nesterova, and N. I. Izraileva, Universal variation of F2-layer critical frequency as characteristics of global ionospheric state, Geomagn. Aeron., 32, 195–197, 1992 (in Russian).
Rao, M. S. J. G. and R. S. Rao, The hysteresis variation in F2-layer pa-rameters, J. Atmos. Terr. Phys., 31, 1119–1125, 1969.
Reiter, R., Phenomena in Atmospheric and Environmental Electricity, Elsevier, 1992.
Smith, P. A. and J. W. King, Long-term relationship between sunspots, solar faculae and the ionosphere, J. Atmos. Terr. Phys., 43, 1057–1063, 1981.
Torr M. R. and D. G. Torr, The seasonal behaviour of the F2-layer of the ionosphere, J. Atmos. Terr. Phys., 35, 2237–2251, 1973.
Yonezawa, T., Semi-annual variations in the peak electrons densities of the F2- and E-layers, J. Radio Res. Lab., 19, 1–22, 1972.