[1] World Health Organization. Coronavirus disease (COVID-19) situation report-133. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200601-covid-19-sitrep-133.pdf. [2020-06-01].https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200601-covid-19-sitrep-133.pdf
[2] Zhu N, Zhang DY, Wang WL, Li XW, Yang B, Song JD, et al. A novel coronavirus from patients with pneumonia in China, 2019. New England J of Med. 2020; 382(8):727 − 733.
[3] Tang XL, Wu CC, Li X, Song YH, Yao XM, Wu XK, et al. On the origin and continuing evolution of SARS-CoV-2. Nat Sci Rev 2020. http://dx.doi.org/10.1093/nsr/nwaa036CrossRef