To cite spmodel in publications use:

  Dumelle M, Higham M, Ver Hoef JM (2023). spmodel: Spatial statistical
  modeling and prediction in R. PLOS ONE 18(3): e0282524.
  https://doi.org/10.1371/journal.pone.0282524

A BibTeX entry for LaTeX users is

  @Article{,
    title = {{spmodel}: Spatial statistical modeling and prediction in {R}},
    author = {Michael Dumelle and Matt Higham and Jay M. {Ver Hoef}},
    journal = {PLOS ONE},
    year = {2023},
    volume = {18},
    number = {3},
    pages = {1--32},
    doi = {10.1371/journal.pone.0282524},
    url = {https://doi.org/10.1371/journal.pone.0282524},
  }