Single-Operator Duodenoscope-Assisted Cholangioscopy Is an Effective Alternative in the Management of Choledocholithiasis Not Removed by Conventional Methods, Including Mechanical Lithotripsy - Farrell, J J; Bounds, B C; Al-Shalabi, S; Jacobson, B C; Brugge, W R; Schapiro, R H; Kelsey, P B (Endoscopy, 2005)