RT Journal Article SR Electronic T1 Oral sex and HIV transmission JF Sexually Transmitted Infections JO Sex Transm Infect FD BMJ Publishing Group Ltd SP 307 OP 308 DO 10.1136/sti.77.5.307 VO 77 IS 5 A1 David A Hawkins YR 2001 UL http://sti.bmj.com/content/77/5/307.abstract AB