RT Journal Article SR Electronic T1 Persistent pain: not a medically unexplained symptom JF British Journal of General Practice JO Br J Gen Pract FD British Journal of General Practice SP 638 OP 639 DO 10.3399/bjgp11X601479 VO 61 IS 591 A1 Amanda C de C Williams A1 Martin Johnson YR 2011 UL http://bjgp.org/content/61/591/638.abstract AB