Langhaug, LF; Cheung, YB; Pascoe, SJS; Chirawu, P; Woelk, G; Hayes, RJ; Cowan, FM; (2011) How you ask really matters: randomised comparison of four sexual behaviour questionnaire delivery modes in Zimbabwean youth. Sexually transmitted infections, 87 (2). pp. 165-173. ISSN 1368-4973 DOI: https://doi.org/10.1136/sti.2009.037374 Full text not available from this repository.