To cite package ‘spphpr’ in publications use:

Shi P, Chen Z, Tan J, Quinn B (2025). spphpr: Spring Phenological Prediction. R package version 1.1.5, https://CRAN.R-project.org/package=spphpr.

Corresponding BibTeX entry:

  @Manual{,
    title = {spphpr: Spring Phenological Prediction},
    author = {Peijian Shi and Zhenghong Chen and Jing Tan and Brady K.
      Quinn},
    year = {2025},
    note = {R package version 1.1.5},
    url = {https://CRAN.R-project.org/package=spphpr},
  }