To cite ProAE in publications use:

  Langlais B, Klanderman M, Noble B, Voss M, Dueck A (2020). _ProAE:
  Tools for PRO-CTCAE Scoring, analysis, and graphical display_.
  <https://CRAN.R-project.org/>.

A BibTeX entry for LaTeX users is

  @Manual{proae,
    title = {ProAE: Tools for PRO-CTCAE Scoring, analysis, and graphical display},
    author = {Blake Langlais and Molly Klanderman and Brie Noble and Molly Voss and Amylou Dueck},
    year = {2020},
    url = {https://CRAN.R-project.org/},
  }