1. Department of Epidemiology; Graduate School of Public Health; University of Pittsburgh; Pittsburgh Pennsylvania
2. California Pacific Medical Center; San Francisco California
3. Division of Epidemiology and Community Health; Department of Medicine; University of Minnesot aand Minneapolis VA Health Care System; Minneapolis Minnesota
4. School of Medicine; Stanford University; Stanford California
5. University of California at San Diego; La Jolla California
6. Oregon Health & Sciences University; Portland Oregon