To cite package ‘mapfit’ in publications use:

  Okamura H (2022). _mapfit: PH/MAP Parameter Estimation_. R package
  version 1.0.0, <https://CRAN.R-project.org/package=mapfit>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {mapfit: PH/MAP Parameter Estimation},
    author = {Hiroyuki Okamura},
    year = {2022},
    note = {R package version 1.0.0},
    url = {https://CRAN.R-project.org/package=mapfit},
  }