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Imrie J, Stephenson JM, Cowan FM, Wanigaratne S, Billington AJ, Copas AJ, French L, French PD, Johnson AM; Behavioural Intervention in Gay Men Project Study Group.Imrie J, et al.BMJ. 2001 Jun 16;322(7300):1451-6. doi: 10.1136/bmj.322.7300.1451.BMJ. 2001.PMID: 11408300Free PMC article.Clinical Trial.