McKenna S, Doward LC. Measuring quality of life in ankylosing spondylitis. Best Pract Res Clin Rheumatol. 2008 Jan 1;6(2):12-4.
Morant SV, Gnanasakthy A. A new approach to the mathematical formulation of lactation curves. Anim Prod Sci. 1989 Oct;49(2):151-62.