Feldman M, Friedman L, Brandt L. 2010. Sleisenger and Fordtran's gastrointestinal and liver disease [9th ed.], CH. 19, 285-322.e8. Philadelphia: Saunders Elsevier.
Jackson P, Raji J. 2011. Evaluation and management of intestinal obstruction. Am Fam Physician 83(2). October 31, 2014. http://www.aafp.org/afp/2011/0115/p159.html.
Vincent J, Abraham E, Moore FA, et al. 2011. Ileus and mechanical bowel obstruction. Textbook of Critical Care, 6th ed.; 106, 806-807, Philadelphia: Elsevier Saunders.
National Institutes of health. National Cancer Institute. Gastrointestinal complications. https://www.cancer.gov/about-cancer/treatment/side-effects/constipation/GI-complications-hp-pdq. Updated September 9, 2016. Accessed September 2016.