To cite package ‘countdata’ in publications use:

  Pham T (2023). _countdata: The Beta-Binomial Test for Count Data_. R
  package version 1.3, <https://CRAN.R-project.org/package=countdata>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {countdata: The Beta-Binomial Test for Count Data},
    author = {Thang Pham},
    year = {2023},
    note = {R package version 1.3},
    url = {https://CRAN.R-project.org/package=countdata},
  }