1. Donnelly, R. F. 1993.Solar - Terrestr. Predict. – IVEdited by: Hruscka, J., Shea, M. A., Smart, D. F. and Heckman, G. 131Boulder
2. Kataja, E. 1986, 1984.Solar-Terrestrial Predictions, MeudonEdited by: Simon, P. A., Hecknaan, G. and Shea, M. A. 35Boulder