RT Journal Article SR Electronic T1 Use of statistical analysis in open extension studies. JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 437 OP 437 VO 33 IS 2 A1 Yusuf Yazici A1 Hasan Yazici YR 2006 UL http://www.jrheum.org/content/33/2/437.abstract AB