Nguyen, Nam P, et al. “Low-Dose-Whole-Lung Radiotherapy for Older Patients With Coronavirus Disease (Covid-19) Pneumonia: A Phase I-II Prospective Non-Randomized Protocol by the International Geriatric Radiotherapy Group”. Archives of Clinical and Biomedical Research, vol. 5, no. 2, Apr. 2021, pp. 201-13, https://fortunejournals.org/ojs/index.php/acbr/article/view/14827.