da Costa Ferreira, Sandro, et al. “Factors Predictive of Proximal Disease Extension and Clinical Course of Patients Initially Diagnosed With Ulcerative Proctitis in an IBD Referral Center”. Turkish Journal of Gastroenterology, vol. 33, no. 4, Jan. 2022, pp. 320-8, doi:10.5152/tjg.2022.21124.