title: Referral bias: a difficult but important topic.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Gibbons
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods*; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D018579:Patient Selection; D011877:Radionuclide Imaging; D012017:Referral and Consultation / Q000706:statistics & numerical data; D012106:Research / Q000706:statistics & numerical data*; D012107:Research Design; D015983:Selection Bias; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000453:epidemiology*