Chaplin, H., Carpenter, L., Raz, A., Nikiphorou, E., Lempp, H., & Norton, S. (2021). Summarizing current refractory disease definitions in rheumatoid arthritis and polyarticular juvenile idiopathic arthritis: systematic review. Rheumatology, 60(8), 3540–3552. https://doi.org/10.1093/rheumatology/keab237