Duodenal varices as an unusual cause of gastrointestinal bleeding due to portal hypertension: A case report - SELÇUK, Haldun; BOYVAT, Fatih; EREN, Serdar; KORKMAZ, Murat; GÜR, Gürden; YILMAZ, Uğur; BOYACIOĞLU, Sedat (Turkish Journal of Gastroenterology, 2004)