Uptake of voluntary counselling and testing among young people participating in an HIV prevention trial: comparison of opt-out and opt-in strategies.
Baisley K, Doyle AM, Changalucha J, Maganja K, Watson-Jones D, Hayes R, Ross D.
PLoS One 2012;7: e42108.
PMID:22848722
PMCID:PMC3405062
DOI:10.1371/journal.pone.0042108