Clip-assisted anchoring method to facilitate submucosal tunnel entry in peroral endoscopic myotomy for severe fibrosis - Yamamoto, Kazuki; Nishikawa, Yohei; Shigeta, Kohei; Ushikubo, Kei; Tanaka, Ippei; Abiko, Satoshi; Inoue, Haruhiro (Endoscopy International Open, 2025)