Szajnbock, Israel, Fernando Lorenzi, Aldo Junqueira Rodrigues Jr., Luis Fernando Correa Zantut, Renato Sérgio Poggetti, Eliana Steinman, and Dario Birolini. 1996. “Gallstone Ileus As a Cause of Upper Intestinal Obstruction”. São Paulo Medical Journal 114 (4):1239-43. https://periodicosapm.emnuvens.com.br/spmj/article/view/2009.