Certolizumab pegol plus methotrexate is significantly more effective than placebo plus methotrexate in active rheumatoid arthritis: findings of a fifty-two-week, phase III, multicenter, randomized, double-blind, placebo-controlled, parallel-group study. - Keystone E; van der Heijde D; Mason D Jr.; Landewé R; van Vollenhoven R; Combe B; Emery P; Strand V; Mease P; Desai C; Pavelka K (Arthritis & Rheumatism, 2008)