Saragih, I. D., I. Suarilah, and I. S. Saragih. “Prognosis of Survival Among Older Adults With COVID-19: A Systematic Review and Meta-Analysis”. International Journal of Health Sciences, vol. 6, no. S5, June 2022, pp. 4429-44, doi:10.53730/ijhs.v6nS5.9576.