Successful resection of protruding tumor with muscle-retracting sign during rectal endoscopic submucosal dissection using isolation method and picking technique with clutch cutter - Abiko, Satoshi; Hirata, Koji; Suzuki, Kazuharu; Kinoshita, Kenji; Hatanaka, Kazuteru; Yamamoto, Yoshiya; Naruse, Hirohito (Endoscopy, 2021)