To cite package ‘XNomial’ in publications use:

  Engels B (2024). _XNomial: Exact Goodness-of-Fit Test for Multinomial
  Data with Fixed Probabilities_. R package version 1.0.4.1,
  <https://CRAN.R-project.org/package=XNomial>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {XNomial: Exact Goodness-of-Fit Test for Multinomial Data with Fixed
Probabilities},
    author = {Bill Engels},
    year = {2024},
    note = {R package version 1.0.4.1},
    url = {https://CRAN.R-project.org/package=XNomial},
  }