1. HealthPartners Institute for Education and Research, Minneapolis, Minnesota
2. Obstetrics and Gynecology, Yale University, New Haven, Connecticut
3. Kaiser Permanente of Northern California, Oakland
4. Kaiser Permanente Southern California, Pasadena
5. Kaiser Permanente Northwest, Portland, Oregon
6. Kaiser Permanente Georgia, Atlanta
7. Institute for Health Research, Kaiser Permanente Colorado, Denver8Department of Ambulatory Care Services, Denver Health, Denver, Colorado
8. Harvard Pilgrim Health Care Institute, Boston, Massachusetts10Harvard Medical School, Boston, Massachusetts
9. Group Health Cooperative, Seattle, Washington
10. Centers for Disease Control and Prevention, Atlanta, Georgia