Visual analog scales in formats other than a 10 centimeter horizontal line to assess pain and other clinical data.
Pincus T, Bergman M, Sokka T, Roth J, Swearingen C, Yazici Y. Visual analog scales in formats other than a 10 centimeter horizontal line to assess pain and other clinical data. J Rheumatol. 2008 Aug; 35(8):1550-8.