Utility of a novel tapered-tip sheath system for preoperative mapping biopsy of biliary tract cancers - Tomoaki Matsumori; Norimitsu Uza; Kazuhiro Okada; Masahiro Shiokawa; Takahisa Maruno; Yoshihiro Nishikawa; Takeshi Kuwada; Yuya Muramoto; Muneji Yasuda; Hajime Yamazaki; Kojiro Taura; Etsuro Hatano; et al. (Endoscopy International Open)