Harrold LR, Reed GW, Magner R, Shewade A, John A, Greenberg JD, Kremer JM. Comparative effectiveness and safety of rituximab versus subsequent anti-tumor necrosis factor therapy in patients with rheumatoid arthritis with prior exposure to anti-tumor necrosis factor therapies in the United States Corrona registry. Arthritis Res Ther. 2015 Sep 18; 17:256.