The institutions that contributed material for this report are:
1. Arecibo Ionospheric Observatory.
2. NASA-Goddard Space Flight Center.
3. Bell Telephone Laboratories.
4. University of Texas.
5. University of Maryland.
6. University of Virginia.
7. Florida State University.
8. Air Force Cambridge Research Laboratories.
9. Stanford University.
10. MIT Lincoln Laboratory.
11. Ohio State University.
12. University of Colorado.
13. National Radio Astronomy Observatory.
14. Jet Propulsion Laboratory.
15. Owens Valley Radio Observatory.
Only a minor attempt has been made to mention work performed at other observatories in the U.S.A.