Arslan, B., T. Yilmaz, V. Erol, and H. Gulay. “Asymptomatic Cholecysto-Enteric Fistula and Gallstone Ileus: Two Case Reports”. Annals of Medical Research, vol. 26, no. 1, May 2021, pp. 0113-6, http://annalsmedres.org/index.php/aomr/article/view/1397.