RT Journal Article SR Electronic T1 Fatigue and psychological states and traits in systemic lupus erythematosus: association or causation? JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 823 OP 823 VO 31 IS 4 A1 Niels Henrik Hjollund A1 Ole Nørby Hansen YR 2004 UL http://www.jrheum.org/content/31/4/823.abstract AB