Sudol-Szopinska, Iwona, et al. “Endosonographic and Manometric Assessment of the Anal Sphincters in Patients Operated on for Crohn’s Disease of the Colon”. Radiology and Oncology, vol. 36, no. 3, Sept. 2002, https://www.radioloncol.com/index.php/ro/article/view/1535.