Predictors of common bile duct stones prior to cholecystectomy: a meta-analysis. - Abboud,P.A.; Malet,P.F.; Berlin,J.A.; Staroscik,R.; Cabana,M.D.; Clarke,J.R.; Shea,J.A.; Schwartz,J.S.; Williams,S.V. (Gastrointest Endosc, 1996)