@article{article6435704b,
title   = {Ultrasonography in the diagnostic work up of malignant tumours of large biliary ducts},
author = {Cerri, Giovanni Guido and Alves, Venâncio Avancini Ferreira and Magalhães, Álvaro Eduardo de Almeida},
year = {1989},
journal   = {Acta Radiológica Portuguesa}
}