To cite package ‘bets.covid19’ in publications use:

  Zhao Q, Ju N (2020). _bets.covid19: The BETS Model for Early Epidemic
  Data_. R package version 1.0.0,
  <https://github.com/qingyuanzhao/bets.covid19>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {bets.covid19: The BETS Model for Early Epidemic Data},
    author = {Qingyuan Zhao and Nianqiao Ju},
    year = {2020},
    note = {R package version 1.0.0},
    url = {https://github.com/qingyuanzhao/bets.covid19},
  }