Easy and effective counter-traction using a clip with a looped thread for colorectal endoscopic submucosal dissection - Indo, Naohiko; Anami, Takahiro; Asaji, Naoki; Urakami, Satoshi; Nishio, Akihiro; Kitamura, Yasuaki; Watanabe, Akihiko (Endoscopy, 2019)