To cite flattabler in publications use:

Samos J (2020). flattabler: Obtaining a Flat Table from Pivot Tables. R package version 1.1.0, https://CRAN.R-project.org/package=flattabler.

Corresponding BibTeX entry:

  @Manual{,
    title = {{flattabler}: Obtaining a Flat Table from Pivot Tables},
    author = {Jose Samos},
    year = {2020},
    note = {R package version 1.1.0},
    url = {https://CRAN.R-project.org/package=flattabler},
  }