Solomon DH, Kremer JM, Fisher M, Curtis JR, Furer V, Harrold LR, Hochberg MC, Reed G, Tsao P, Greenberg JD. Comparative cancer risk associated with methotrexate, other non-biologic and biologic disease-modifying anti-rheumatic drugs. Semin Arthritis Rheum. 2014 Feb; 43(4):489-97.