To cite package ‘akima’ in publications use:

Akima H, Gebhardt A (2025). akima: Interpolation of Irregularly and Regularly Spaced Data. R package version 0.6-3.6, https://CRAN.R-project.org/package=akima.

Corresponding BibTeX entry:

  @Manual{,
    title = {akima: Interpolation of Irregularly and Regularly Spaced
      Data},
    author = {Hiroshi Akima and Albrecht Gebhardt},
    year = {2025},
    note = {R package version 0.6-3.6},
    url = {https://CRAN.R-project.org/package=akima},
  }