Citation Select	Collins R, Burch J, Cranny G, Aguiar-Ibáñez R, Craig D, Wright K, Berry E, Gough M, Kleijnen J, Westwood M, Duplex ultrasonography, magnetic resonance angiography, and computed tomography angiography for diagnosis and assessment of symptomatic, lower limb peripheral arterial disease: systematic review. BMJ. 2007 Jun 16;334(7606):1257