1. Herman, J. R., Goldberg, R. A., Sun, Weather and Climate, Washington: NASA, 1978.
2. Obridko, V., Belov, A., Rivin, Y., The main features of solar cycle 22 and some forecasts of cycle 23, in Proc. of Workshop on Solar-Terrestrial Prediction (ed. Hruska, J.Y.), Ottawa: NOAA, USA, 1992, 261.
3. Thompson, R. J., A technique for predicting the amplitude of the solar cycle, Solar Physics, 1993, 148: 383.
4. Wang Jialong, Zhang Guiqing, On the progress of long-term and medium-term solar activity predictions, Progress in Geophysics, 1994, 9(Suppl.): 1.
5. Han Yanben, Wang Jialong, Preliminary verification of sunspot predictions of cycle 23 by the method of similar cycles, Chinese Astronomy & Astrophysics, 1999, 23: 139.