To cite package ‘vatcheckapi’ in publications use:

Kukacka D (2023). vatcheckapi: Client for the 'vatcheckapi.com' VAT Validation API. R package version 0.1.0, https://CRAN.R-project.org/package=vatcheckapi.

Corresponding BibTeX entry:

  @Manual{,
    title = {vatcheckapi: Client for the 'vatcheckapi.com' VAT
      Validation API},
    author = {Dominik Kukacka},
    year = {2023},
    note = {R package version 0.1.0},
    url = {https://CRAN.R-project.org/package=vatcheckapi},
  }