1. Center for AIDS Prevention Studies, University of California, San Francisco, San Francisco, California.
2. Center for Community Health, University of California, Los Angeles, Los Angeles, California.
3. HIV Center for Clinical and Behavioral Studies, New York State Psychiatric Institute and Columbia University, New York, New York.
4. Center for Health Studies, Group Health Cooperative, Seattle, Washington.
5. Center for AIDS Intervention Research, Medical College of Wisconsin, Milwaukee, Wisconsin.