Michele Marini, et al. “Endoscopic Versus Surgical Treatment for a Rare Form of Gallstone Ileus: Bouveret’s Syndrome”. Annali Italiani Di Chirurgia, vol. 89, no. 2, Mar. 2018, pp. 162-7, https://annaliitalianidichirurgia.it/index.php/aic/article/view/1059.