RT Journal Article SR Electronic T1 Sexually transmitted diseases JF The British Journal of Venereal Diseases JO Br J Vener Dis FD BMJ Publishing Group Ltd SP 502 OP 508 DO 10.1136/sti.46.6.502 VO 46 IS 6 YR 1970 UL http://sti.bmj.com/content/46/6/502.abstract AB