To cite package ‘interp’ in publications use:

Gebhardt A, Bivand R, Sinclair D (2024). interp: Interpolation Methods. R package version 1.1-6, https://CRAN.R-project.org/package=interp.

Corresponding BibTeX entry:

  @Manual{,
    title = {interp: Interpolation Methods},
    author = {Albrecht Gebhardt and Roger Bivand and David Sinclair},
    year = {2024},
    note = {R package version 1.1-6},
    url = {https://CRAN.R-project.org/package=interp},
  }