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 and Cyrille Violle (2017). “funrar: An R package to characterize functional rarity.” Diversity and Distributions. doi: 10.1111/ddi.12629, http://onlinelibrary.wiley.com/doi/10.1111/ddi.12629/abstract.

Matthias Grenié, Pierre Denelle, Caroline M. Tucker, François Munoz and Cyrille Violle (2017). funrar: An R package to characterize functional rarity. R package version 1.2.1, 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 =
      {http://onlinelibrary.wiley.com/doi/10.1111/ddi.12629/abstract},
    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 1.2.1},
    url = {https://cran.r-project.org/package=funrar},
  }