To cite redistmetrics in publications use:

  Kenny C, McCartan C, Fifield B, Imai K (2023). _redistmetrics:
  Redistricting Metrics_. R package,
  <https://alarm-redist.org/redistmetrics/>.

A BibTeX entry for LaTeX users is

  @Manual{redistmetrics,
    title = {{redistmetrics}: Redistricting Metrics},
    author = {Christopher T. Kenny and Cory McCartan and Ben Fifield and Kosuke Imai},
    year = {2023},
    note = {R package},
    url = {https://alarm-redist.org/redistmetrics/},
  }