To cite package ‘assertive.base’ in publications use:

  Cotton R (2026). _assertive.base: A Lightweight Core of the
  'assertive' Package_. R package version 0.0.9.9001,
  <https://bitbucket.org/richierocks/assertive.base>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {assertive.base: A Lightweight Core of the 'assertive' Package},
    author = {Richard Cotton},
    year = {2026},
    note = {R package version 0.0.9.9001},
    url = {https://bitbucket.org/richierocks/assertive.base},
  }