9Jain S K, Stein R, Bhuva M, et al. Pigtail stents: an alternative in the treatment of difficult bile duct stones[J]. Gastrointest Endosc, 2000, 52(4):490-493.
10Moon J H, Cha S W, Ryu C B, et al. Endoscopic treatment of retained bile-duct stones by using a balloon catheter for electrohydraulic lithotripsy without cholangioscopy[J]. Gastrointest Endosc, 2004, 60(4): 562.