To cite package ‘pdi’ in publications use:

  Finch J (2026). _pdi: Phenotypic Index Measures for Oak Decline
  Severity_. R package version 0.4.3,
  <https://CRAN.R-project.org/package=pdi>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {pdi: Phenotypic Index Measures for Oak Decline Severity},
    author = {Jasen Finch},
    year = {2026},
    note = {R package version 0.4.3},
    url = {https://CRAN.R-project.org/package=pdi},
  }