To cite rflexscan in publications use:

  Otani T, Takahashi K (2021). “Flexible Scan Statistics for Detecting
  Spatial Disease Clusters: The rflexscan R Package.” _Journal of
  Statistical Software_, *99*(13), 1-29. doi:10.18637/jss.v099.i13
  <https://doi.org/10.18637/jss.v099.i13>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Flexible Scan Statistics for Detecting Spatial Disease Clusters: The {rflexscan} {R} Package},
    author = {Takahiro Otani and Kunihiko Takahashi},
    journal = {Journal of Statistical Software},
    year = {2021},
    volume = {99},
    number = {13},
    pages = {1--29},
    doi = {10.18637/jss.v099.i13},
  }