Garcia, J. P., Sousa, J. T., Silva, E., Soares, E., Pedroso, C., & Cid, M. O. (1993). Intraoperative echography in biliary tract surgery. A comparative study of intraoperative echography/cholangiography in the detection of calculi in the common bile duct. Acta Médica Portuguesa, 6(3-4), 123–8. https://doi.org/10.20344/amp.3073