To cite the permutations package in publications use:

Robin K. S. Hankin (2020). “Introducing the permutations package.” SoftwareX. https://doi.org/10.1016/j.softx.2020.100453.

Corresponding BibTeX entry:

  @Article{,
    title = {{Introducing the permutations package}},
    author = {{Robin K. S. Hankin}},
    journal = {SoftwareX},
    year = {2020},
    url = {https://doi.org/10.1016/j.softx.2020.100453},
  }