[1] CDC, Arthrit Program, Atlanta, GA 30341 USA
[2] Sue Binder Consulting Inc, Atlanta, GA USA
[3] SciMetrika, Atlanta, GA USA
[4] Univ Penn, Dept Dermatol, Philadelphia, PA 19104 USA
[5] Univ Penn, Dept Biostat & Epidemiol, Philadelphia, PA 19104 USA
[6] Univ Penn, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[7] Natl Psoriasis Fdn, Portland, OR USA
[8] SciMetrika, Durham, NC USA