To cite package ‘gridExtra’ in publications use:

Auguie B (2020). gridExtra: Miscellaneous Functions for "Grid" Graphics. R package version 2.3, https://github.com/baptiste/gridextra.

Corresponding BibTeX entry:

  @Manual{,
    title = {gridExtra: Miscellaneous Functions for "Grid" Graphics},
    author = {Baptiste Auguie},
    year = {2020},
    note = {R package version 2.3},
    url = {https://github.com/baptiste/gridextra},
  }