To cite package ‘spphpr’ in publications use:

  Shi P, Chen Z, Quinn B (2024). _spphpr: Spring Phenological
  Prediction_. R package version 0.1.4,
  <https://CRAN.R-project.org/package=spphpr>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {spphpr: Spring Phenological Prediction},
    author = {Peijian Shi and Zhenghong Chen and Brady K. Quinn},
    year = {2024},
    note = {R package version 0.1.4},
    url = {https://CRAN.R-project.org/package=spphpr},
  }