Cho SH, Lee YS, Kim YJ, Sohn CH, Ahn S, Seo DW, Kim WY, Lee JH, Lim KS. Outcomes and Role of Urgent Endoscopy in High-Risk Patients With Acute Nonvariceal Gastrointestinal Bleeding. Clin Gastroenterol Hepatol. 2018 Mar;16(3):370-377. doi: 10.1016/j.cgh.2017.06.029. Epub 2017 Jun 19. PMID: 28634135