To cite package ‘add2ggplot’ in publications use:

Li J, Ryo N (2020). add2ggplot: Add to 'ggplot2'. R package version 0.3.0, https://github.com/jiaxiangbu/add2ggplot.

Corresponding BibTeX entry:

  @Manual{,
    title = {add2ggplot: Add to 'ggplot2'},
    author = {Jiaxiang Li and Nakagawara Ryo},
    year = {2020},
    note = {R package version 0.3.0},
    url = {https://github.com/jiaxiangbu/add2ggplot},
  }