1. Armstrong, T. P., Laird, C. M., Venkatesan, D., Krishnaswamy, S., and Rosenberg, T. J.: 1989, J. Geophys. Res. 94, A4, 3543.
2. Bieber, J. W. and Pomerantz, M. A.: 1986, Astrophys. J. 303, 843.
3. Crutzen, P. J., Isaksen, I., and Reid, G.: 1975, Science 189, 457.
4. Damon, P. E., Cheng, S., and Linck, T. W.: 1988, 13th International Radiocarbon Conference, June 20?25, Dubrovnik, Yugoslavia.
5. Dreschhoff, G., Zeller, E. J., and Parker, B. C.: 1983, in B. M. McCormac (ed.), Weather and Climate Responses to Solar Variations, Colorado Assoc. Univ. Press, Boulder, p. 225.