Jacobson BA, Sharon J, Shan H, Shlomchik M, Weigert MG, Marshak-Rothstein A. An isotype switched and somatically mutated rheumatoid factor clone isolated from a MRL-lpr/lpr mouse exhibits limited intraclonal affinity maturation. J Immunol. 1994 May 01; 152(9):4489-99.