"Bleeding in the Digestive Tract". The National Institute of Diabetes and Digestive and Kidney Diseases. September 17, 2014. Archived from the original on 21 February 2015. Retrieved 6 March 2015.
"Bleeding in the Digestive Tract". The National Institute of Diabetes and Digestive and Kidney Diseases. September 17, 2014. Archived from the original on 21 February 2015. Retrieved 6 March 2015.