1. Report on the Global HIV/AIDS Epidemic—December 1999;Joint United Nations Programme on HIV/AIDS and The World Health Organization,1999
2. Gay men report high rates of unprotected anal sex with partners of unknown or discordant HIV status;Ekstrand;AIDS,1999
3. Increase in unprotected anal intercourse with casual partners among Sydney gay men in 1996-98;Van de Ven;Aust N Z J Public Health,1998