Liu SY, Trope GE, Buys YM, El-Defrawy SR, Khan AM, Jin YP. Visual impairment and the Ontario disability support program. Can J Ophthalmol. 2020 Jun;55(3):212-20. doi: 10.1016/j.jcjo.2019.12.009
McKenna S, Doward LC. Measuring quality of life in ankylosing spondylitis. Best Pract Res Clin Rheumatol. 2008 Jan 1;6(2):12-4.