@misc{misc85c52e3e,
title   = {Contribution of ultrasonography in the diagnosis of malignant tumors of the biliary ducts},
author = {Cerri, Giovanni Guido and Ferreyra, N P and Alves, Venâncio Avancini Ferreira and Magalhães, Álvaro Eduardo de Almeida and Bettarello, Agostinho},
year = {1986},
booktitle   = {World Congress on Gastroenterology}
}