Aziz M, Dasari CS, Zafar Y, Fatima R, Haghbin H, Alyousif ZA, Lee-Smith W, Perisetti A, Nawras A, Garg S, Inamdar S, Tharian B. Does timing of endoscopy affect outcomes in patients with upper gastrointestinal bleeding: a systematic review and meta-analysis. Eur J Gastroenterol Hepatol. 2021 08 01; 33(8):1055-1062.