RT Journal Article SR Electronic T1 Interpreting differences over time in patient self-evaluation JF British Journal of General Practice JO Br J Gen Pract FD British Journal of General Practice SP 472 OP 472 VO 55 IS 515 A1 Michael Robling A1 Kerenza Hood A1 Chris Butler YR 2005 UL http://bjgp.org/content/55/515/472.1.abstract AB