1. L. J. Lanzerotti, Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974, and the University of Florida, Gainesville, FL 32611, USA.
2. K. Rinnert, Max-Planck-Institut für Aeronomy, D-37191 Katlenburg-Lindau, Germany.
3. G. Dehmel, F. O. Gliem, J. Bach, Universität Braunschweig, D-38106 Braunschweig, Germany.
4. E. P. Krider, University of Arizona, Tucson, AZ 85721, USA.
5. M. A. Uman, University of Florida, Gainesville, FL 32611, USA.