1. Berens, D. I. Gallstone impacted in duodenal bulb.Gastroenterology 36:881, 1959.
2. Buetow, G. N., andCrampton, R. S. Gallstone ileus.Arch. Surg. 86:505, 1963.
3. Contro, L., andDioguardi, N. Illustrazione di un caso di sindrome di Bouveret.Min. Med. 52:2295, 1961.
4. Courvoisier, L. G. Casuistisch-Statistische Beiträge zur Pathologie und Chirurgie der Gällenwäge. Vogel, Leipzig, 1890.
5. DeFeo, E., andMeigher, S. C. Gallstones impacted in the stomach and duodenal bulb demonstrated by roentgenologic examination.Am. J. Roentgenol. 77: 40, 1957.