The ‘Antiretrovirals, Sexual Transmission Risk and Attitudes’ (ASTRA) Study. Design, Methods and Participant Characteristics. - Speakman, Andrew; Rodger, Alison; Phillips, Andrew N.; Gilson, Richard; Johnson, Margaret; Fisher, Martin; Ed Wilkins; Anderson, Jane; O’Connell, Rebecca; Lascar, Monica; Aderogba, Kazeem; Edwards, Simon; et al. (PLoS ONE, 2013)