1. Space Science Division; U.S. Naval Research Laboratory; Washington, D.C. USA
2. Centre for Research in Earth and Space Science; York University; North York, Ontario Canada
3. Department of Earth and Space Sciences; University of Washington; Seattle Washington USA
4. British Antarctic Survey; Cambridge UK
5. Department of Physics and Astronomy; Clemson University; Clemson South Carolina USA
6. Space Physics Research Laboratory; University of Michigan; Ann Arbor Michigan USA
7. Haystack Observatory; Massachusetts Institute of Technology; Westford Massachusetts USA
8. Arecibo Observatory; Cornell University; Arecibo Puerto Rico