RT Journal Article SR Electronic T1 Swinging: if you do not ask you may not find, but you need to JF Sexually Transmitted Infections JO Sex Transm Infect FD BMJ Publishing Group Ltd SP 381 OP 382 DO 10.1136/sextrans-2017-053187 VO 93 IS 6 A1 Catherine H Mercer YR 2017 UL http://sti.bmj.com/content/93/6/381.abstract AB