Upper Gastrointestinal Tract Bleeding as a Predictor of Mortality in COVID-19 Patients Admitted to RSUP Dr. Sardjito, Yogyakarta, IndonesiaTabita Padmaya Setiawan, Eko Budiono, Neneng Ratnasari and Dhite Bayu NugrohoBIO Web Conf., 75 (2023) 01009DOI: https://doi.org/10.1051/bioconf/20237501009