1. U.S. Geological Survey, Menlo Park, California 94025
2. U.S. Geological Survey, Flagstaff, Arizona 86001
3. Lowell Observatory, Flagstaff, Arizona 86001
4. Science Applications, Inc., Pasadena, California 91101
5. Jet Propulsion Laboratory, Pasadena, California 91103
6. Science Applications, Inc., Pasadena
7. Jet Propulsion Laboratory, Pasadena
8. University of Santa Clara, Santa Clara, California 95053
9. University of London Observatory, London, NW72QS, England
10. University of Arizona, Tucson 85721
11. U.S. Geological Survey, Flagstaff
12. Cornell University, Ithaca, New York 14853