To cite package ‘choroplethrMaps’ in publications use:

Lamstein A (2018). choroplethrMaps: Contains Maps Used by the 'choroplethr' Package. R package version 1.0.1, https://github.com/arilamstein/choroplethrmaps.

Corresponding BibTeX entry:

  @Manual{,
    title = {choroplethrMaps: Contains Maps Used by the 'choroplethr'
      Package},
    author = {Ari Lamstein},
    year = {2018},
    note = {R package version 1.0.1},
    url = {https://github.com/arilamstein/choroplethrmaps},
  }