An evaluation of the feasibility of an expanded indication of endoscopic submucosal dissection for ulcer positive early gastric cancer: a case-control study from two medical centers - Gao, Jian-Peng; Li, Meng-Jiao; Feng, Tie-Nan; Liu, Chao; Zhu, Zheng-Lun; Zhang, Ben-Yan; Yan, Min; Zhu, Zheng-Gang (Annals of Translational Medicine, 2020)