1. Wyllie R. Foreign bodies in the gastrointestinal tract. Curr Opin Pediatr. 2006; 18(5):563–4.
2. Chiu YH, Hou SK, Chen SC, et al. Diagnosis and endoscopic management of upper gastrointestinal foreign bodies. Am J Med Sci. 2012;343(3):192–5.
3. Evans DC, Wojda TR, Jones CD, et al. Intentional ingestions of foreign objects among prisoners: a review. World J Gastrointest Endosc. 2015;7(3):162–8.