Hashizume, Hideo, et al. “Epstein-Barr Virus-Positive Mucocutaneous Ulcers As a Manifestation of Methotrexate-Associated B-Cell Lymphoproliferative Disorders”. Acta Dermato-Venereologica, vol. 92, no. 3, Nov. 2011, pp. 276-7, doi:10.2340/00015555-1274.