McKenna SP, Doward LC. How should we measure quality of life in ankylosing spondylitis? Rheumatol Pract. 2008;6(2):12-4.
Estrada CA, Unterborn JN, Price J, Thompson D, Gibson L. Judging the effectiveness of clinical pathways for pneumonia: the role of risk adjustment. Eff Clin Pract. 2000 Sep 1;3(5):221-8.