1. Khan MA: Update on spondyloarthropathies. Ann Intern Med 2002, 136:896–907.
2. Zochling J, Braun J, van der Heijde D: Assessments in ankylosing spondylitis. Best Pract Res Clin Rheumatol 2006, 20:521–537.
3. Anderson JJ, Baron G, van der Heijde D, et al.: Ankylosing spondylitis assessment group preliminary definition of short-term improvement in ankylosing spondylitis. Arthritis Rheum 2001, 44:1876–1886.
4. Calin A, Garrett SL, Whitelock HC, et al.: A new approach to defining functional ability in ankylosing spondylitis: the development of the Bath Ankylosing Spondylitis Functional Index. J Rheumatol 1994, 21:2281–2285.
5. Garrett SL, Jenkinson T, Kennedy LG, et al.: New approach to defining disease status in ankylosing spondylitis: the Bath ankylosing spondylitis disease activity index. J Rheumatol 1994, 21:2286–2291.