Construct validity and responsiveness of feasible composite disease activity measures for use in daily clinical practice in patients with psoriatic arthritis oleh Ilja Tchetverikov, Marijn Vis, William Tillett, Maikel van Oosterhout, Faouzia Fodili, Fazira R. Kasiem, Marc R. Kok, Jolanda J. Luime, Lindy-Anne Korswagen, Natasja H.A.M. Denissen, Yvonne P.M. Goekoop-Ruiterman, Johanna M.W. Hazes