Long-term effectiveness of tocilizumab in patients with rheumatoid arthritis, stratified by number of previous treatment failures with biologic agents: results from the German RABBIT cohort - Baganz, L.; Richter, Adrian; Kekow, J.; Bussmann, A.; Krause, A.; Stille, C.; Listing, J.; Zink, A.; Strangfeld, A. (Rheumatol Int, 2018)