1. University College London; Research Department of Primary Care and Population Health; Upper Third Floor, Royal Free Hospital Rowland Hill Street London UK NW3 2PF
2. University College London; Centre for Sexual Health and HIV Research; Mortimer Market Centre, off Capper Street London UK WC1E 6JB
3. Archway Healthcare Library; Holborn Union Building Archway Campus, Highgate Hill London UK N19 5LW
4. University of Brighton; Brighton and Sussex Medical School; Mayfield House Room 311 Falmer Brighton UK BN1 9PH