To cite package ‘geosphere’ in publications use:

  Hijmans R (2023). _geosphere: Spherical Trigonometry_. R package
  version 1.5-19, <https://github.com/rspatial/geosphere>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {geosphere: Spherical Trigonometry},
    author = {Robert J. Hijmans},
    year = {2023},
    note = {R package version 1.5-19},
    url = {https://github.com/rspatial/geosphere},
  }