- The comparative effectiveness of tumor necrosis factor-blocking agents in patients with rheumatoid arthritis and patients with ankylosing spondylitis: a six-month, longitudinal, observational, multicenter study. Heiberg, M.S., Nordvåg, B.Y., Mikkelsen, K., Rødevand, E., Kaufmann, C., Mowinckel, P., Kvien, T.K. Arthritis Rheum. (2005)