Endoscopic four-branched stent-in-stent deployment of self-expandable metal stents in malignant hilar biliary obstruction - Kaneko, Junichi; Yamada, Takanori; Fukita, Kyoichi; Tsuji, Atsushi; Nishino, Masafumi; Takahashi, Yurimi; Sasada, Yuzo (Endoscopy, 2021)