The new Childhood Arthritis and Rheumatology Research Alliance (CARRA) registry: design, rationale, and characteristics of patients enrolled in the first 12 months. - Beukelman, Timothy; Yukiko Kimura; Ilowite, Norman T.; Kelly Mieszkalski; Natter, Marc D.; Burrell, Grendel; Best, Brian; Jones, Jason; Schanberg, Laura E. (Pediatric Rheumatology, 2017)