1. National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973
2. Medical Department, Brookhaven National Laboratory, Upton, New York 11973
3. CSRRI, Illinois Institute of Technology, 3301 South Dearborn, Chicago, Illinois 60616
4. Schering AG, Muellerstr. 178 13342 Berlin, Germany