RT Journal Article SR Electronic T1 Spheres of medical influence JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP 387 OP 391 DO 10.7861/clinmedicine.6-4-387 VO 6 IS 4 A1 Carol Black YR 2006 UL http://www.rcpjournals.org/content/6/4/387.abstract AB