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Garcia, J. P.; Sousa, J. T.; Silva, E.; Soares, E.; Pedroso, C.; Cid, M. O. Intraoperative Echography in Biliary Tract Surgery. A Comparative Study of Intraoperative echography/Cholangiography in the Detection of Calculi in the Common Bile Duct. Acta Med Port 1993, 6, 123-8.