RT Journal Article SR Electronic T1 2 or 4 sessions of counselling reduced occurrence of sexually transmitted diseases JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 79 OP 79 DO 10.1136/ebm.1999.4.79 VO 4 IS 3 YR 1999 UL http://ebm.bmj.com/content/4/3/79.abstract AB