To cite package ‘skellam’ in publications use:

  Lewis J, Brown P, Tsagris M (2025). _Densities and Sampling for the
  Skellam Distribution_. R package version 0.2.4,
  <https://r-forge.r-project.org/projects/healthqueues/>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {Densities and Sampling for the Skellam Distribution},
    author = {Jerry W Lewis and Patrick E Brown and Michail Tsagris},
    year = {2025},
    note = {R package version 0.2.4},
    url = {https://r-forge.r-project.org/projects/healthqueues/},
  }