To cite funrar in publications use the reference article or the second reference specifying the package version number

Matthias Grenié, Pierre Denelle, Caroline M. Tucker, François Munoz, Cyrille Violle (2017). “funrar: An R package to characterize functional rarity.” Diversity and Distributions. doi:10.1111/ddi.12629. https://onlinelibrary.wiley.com/doi/10.1111/ddi.12629.

Matthias Grenié, Pierre Denelle, Caroline M. Tucker, François Munoz, Cyrille Violle (2017). funrar: An R package to characterize functional rarity. R package version 1.5.0, https://cran.r-project.org/package=funrar.

Corresponding BibTeX entries:

  @Article{,
    title = {funrar: {An} {R} package to characterize functional
      rarity},
    journal = {Diversity and Distributions},
    author = {{Matthias Grenié} and {Pierre Denelle} and {Caroline M.
      Tucker} and {François Munoz} and {Cyrille Violle}},
    year = {2017},
    url = {https://onlinelibrary.wiley.com/doi/10.1111/ddi.12629},
    doi = {10.1111/ddi.12629},
  }

  @Manual{,
    title = {funrar: {An} {R} package to characterize functional
      rarity},
    author = {{Matthias Grenié} and {Pierre Denelle} and {Caroline M.
      Tucker} and {François Munoz} and {Cyrille Violle}},
    year = {2017},
    note = {R package version 1.5.0},
    url = {https://cran.r-project.org/package=funrar},
  }