1. Rush Medical College, Chicago, Illinois 60612
2. Harvard University School of Public Health Statistical and Data Analysis Center, Boston, Massachusetts 02215
3. University of North Carolina, Chapel Hill, North Carolina 27514
4. University of Alabama Birmingham, Birmingham, Alabama 35233
5. New York University Medical School, New York, New York 10016
6. Indiana University School of Medicine, Indianapolis, Indiana 46202
7. University of Rochester Medical School, Rochester, New York 14642
8. Northwestern University Medical School, Chicago, Illinois 60611