1. a Center for Sexual Health Promotion, Indiana University , Bloomington , USA
2. b HIV Center for Clinical and Behavioral Studies, Columbia University , New York , USA
3. c New York State Psychiatric Institute , New York , USA
4. d Step Up, Inc , Indianapolis , USA
5. e School of Medicine, Emory University , Atlanta , USA
6. f Department of Epidemiology and Biostatistics , Indiana University , Bloomington , USA
7. g Division of Infectious Medicine , Indiana University , Indianapolis , USA
8. h Department of Applied Health Science , Indiana University , Bloomington , USA
9. i Division of Adolescent Medicine , Indiana University , Indianapolis , USA