Chen R, Wei Y, Cai Q, Duan S, Ren D, Shen J, He D, Fang M, Lv K, Cheng N, Sun S. The PADI4 gene does not contribute to genetic susceptibility to rheumatoid arthritis in Chinese Han population. Rheumatology International. 2010 Jun 20;31(12):1631–4. doi: 10.1007/s00296-010-1519-x.