1. Center for Health Promotion, Group Health Cooperative, Seattle, Washington
2. HIV/AIDS Program, Group Health Cooperative, Seattle, Washington
3. Center for Health Studies, Group Health Cooperative, Seattle, Washington
4. Centers for Disease Control and Prevention, Division of HIV/AIDS Prevention, Behavioral Intervention Research Branch, Atlanta, Georgia
5. Center for Health Promotion and Department of Preventive Care, Group Health Cooperative, Seattle, Washington
6. Center for Health Studies and Department of Preventive Care, Group Health Cooperative, Seattle, Washington