1. Department of Infectious Diseases, Rongcheng Hospital Affiliated to Shandong First Medical University, Rongcheng, P.R.China
2. Department of Human Resources, Rongcheng Hospital Affiliated to Shandong First Medical University, Rongcheng, P.R.China
3. Department of Respiratory and Critical Care Medicine, Rongcheng Hospital Affiliated to Shandong First Medical University, Rongcheng, P.R.China
4. Library Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, P.R.China