M CEike, G B NNordang, T HKarlsen, K MBoberg, M H Vatn on behalf of the IBSEN study group, KDahl-Jørgensen, K SRønningen, GJoner, BFlatø, ABergquist, EThorsby, ØFørre, T KKvien, D EUndlien, B ALie
Annals of the Rheumatic Diseases Sep 2008, 67 (9) 1287-1291; DOI: 10.1136/ard.2007.077826