Pavelka K,Uebelhart D. Efficacy evaluation of highly purified intra-articular hyaluronic acid (Sinovial((R))) versus hylan G-F20 (Synvisc((R))) in the treatment of symptomatic knee osteoarthritis. A double-blind, controlled, randomized, parallel-group non-inferiority study. Osteoarthritis Cartilage 2011 Nov;19(11):1294-1300.