Nicholson, A; Ford, E; Davies, KA; Smith, HE; Rait, G; Tate, AR; Petersen, I; (2013) Optimising use of electronic health records to describe the presentation of rheumatoid arthritis in primary care: a strategy for developing code lists. PLoS One , 8 (2) , Article e54878. 10.1371/journal.pone.0054878. Green open access