McKenna SP, Doward LC. How should we measure quality of life in ankylosing spondylitis? Rheumatol Pract. 2008;6(2):12-4.
Willett W, Greenland S, MacMahon B, Trichopoulos D, Rothman KJ, Thomas D. The discipline of epidemiology. Science. 1995 Sep 8;269(5229):1325-6. doi: 10.1126/science.7660105
Rothman KJ. Journal policies on conflict of interest. Science. 1993 Sep 24;261(5129):1661. doi: 10.1126/science.8378766