To cite 'ggsignif' in publications use:

Constantin A, Patil I (2021). “ggsignif: R Package for Displaying Significance Brackets for 'ggplot2'.” PsyArxiv. doi:10.31234/osf.io/7awm6, https://psyarxiv.com/7awm6.

Corresponding BibTeX entry:

  @Article{,
    title = {{ggsignif}: R Package for Displaying Significance Brackets
      for {'ggplot2'}},
    author = {Ahlmann-Eltze Constantin and Indrajeet Patil},
    year = {2021},
    journal = {PsyArxiv},
    url = {https://psyarxiv.com/7awm6},
    doi = {10.31234/osf.io/7awm6},
  }