How does online postal self-sampling (OPSS) shape access to testing for sexually transmitted infections (STIs)? A qualitative study of service users oleh Tommer Spence, Alison Howarth, David Reid, Jessica Sheringham, Vanessa Apea, David Crundwell, Sara Day, Claire Dewsnap, Louise Jackson, Catherine H. Mercer, Hamish Mohammed, Jonathan D. C. Ross, Ann Sullivan, Andy Williams, Andrew Winter, Geoff Wong, Fiona Burns, Jo Gibbs