Using digital tools in the recruitment and retention in randomised controlled trials: survey of UK Clinical Trial Units and a qualitative study oleh Amanda Blatch-Jones, Jacqueline Nuttall, Abby Bull, Louise Worswick, Mark Mullee, Robert Peveler, Stephen Falk, Neil Tape, Jeremy Hinks, Athene J. Lane, Jeremy C. Wyatt, Gareth Griffiths