1. Environmental Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892.
2. Milton S. Hershey Medical Center of the Pennsylvania State University, Hershey 17033.
3. Institute of Cancer Research, Radium Stationen DK-8000, Aarhus, Denmark.
4. ORI, Inc., Bethesda, MD 20014.
5. National Institute on Drug Abuse, Rockville, MD 20852.
6. Medical Arts Center Hospital, New York, NY 10019.
7. Department of Medicine, George Washington University Hospital, Washington, DC 20037.
8. Department of Medicine, Flushing Hospital, New York, NY 11355.
9. Laboratory of Tumor Cell Biology, National Cancer Institute, Bethesda, MD 20892.