RT Journal Article SR Electronic T1 Gangs and sexual violence and exploitation JF Sexually Transmitted Infections JO Sex Transm Infect FD BMJ Publishing Group Ltd SP 4 OP 4 DO 10.1136/sextrans-2012-050940 VO 89 IS 1 A1 Claire Brookings YR 2013 UL http://sti.bmj.com/content/89/1/4.abstract AB