Comparison of patients hospitalized with COVID-19, H7N9 and H1N1 oleh Li-Si Deng, Jing Yuan, Li Ding, Yuan-Li Chen, Chao-Hui Zhao, Gong-Qi Chen, Xing-Hua Li, Xiao-He Li, Wen-Tao Luo, Jian-Feng Lan, Guo-Yu Tan, Sheng-Hong Tang, Jin-Yu Xia, Xi Liu