RT Journal Article SR Electronic T1 Problems with the definition of axial and peripheral disease patterns in psoriatic arthritis. JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 974 OP 977 VO 32 IS 6 A1 William J Taylor A1 Hans-Georg Zmierczak A1 Philip S Helliwell YR 2005 UL http://www.jrheum.org/content/32/6/974.abstract AB