To cite package ‘popularitree’ in publications use:

  O'Meara B (2018). _popularitree: Subsamples a tree to get popular
  taxa_. R package version 0.0.0.9000,
  <https://github.com/bomeara/popularitree>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {popularitree: Subsamples a tree to get popular taxa},
    author = {Brian O'Meara},
    year = {2018},
    note = {R package version 0.0.0.9000},
    url = {https://github.com/bomeara/popularitree},
  }