Hibbard, 2005, Health Services Research, 40, 1918, 10.1111/j.1475-6773.2005.00438.x
Hibbard, 2004, Health Services Research, 39, 1005, 10.1111/j.1475-6773.2004.00269.x
Von Korff, 1997, Annals of Internal Medicine, 127, 1097, 10.7326/0003-4819-127-12-199712150-00008