1. Macquarie Univ. (Australia)
2. GMTO Corp. (United States)
3. NASA Goddard Space Flight Ctr. (United States)
4. The Pennsylvania State Univ. (United States)
5. Univ. of Pennsylvania (United States)
6. The Univ. of Chicago (United States)
7. Landessternwarte Heidelberg (Germany)
8. Physical Research Lab. (United States)