Original Article
Comparison of severe and critical COVID-19 patients imported from Russia with and without influenza A infection in Heilongjiang Province: a retrospective study
Qingqing Dai, Ming Ye, Zhiqiang Tang, Kaijiang Yu, Yang Gao, Zhenyu Yang, Junbo Zheng, Shu Zuo, Yan Liu, Fengjie Xie, Qiuyuan Han, Hua He, Hongliang Wang
