Keyashian, K., E. Duregon, B. Brinkerhoff, L. Bradley, B. Larson, J. Lim, N. Modiano, J. Collins, T. Morgan, and J. Hooper. “Uses and Limitations of IgG4 Positive Plasma Cells in Evaluating Ulcerative Colitis”. Journal of Gastrointestinal and Liver Diseases, Vol. 26, no. 4, Dec. 2017, pp. 425-9, doi:10.15403/jgld.2014.1121.264.igg.