To cite the psych package in publications use:

Revelle W (2019). psych: Procedures for Psychological, Psychometric, and Personality Research. Northwestern University, Evanston, Illinois. R package version 1.9.12, https://CRAN.R-project.org/package=psych.

Corresponding BibTeX entry:

  @Manual{,
    title = {psych: Procedures for Psychological, Psychometric, and
      Personality Research},
    author = {William Revelle},
    organization = { Northwestern University},
    address = { Evanston, Illinois},
    year = {2019},
    note = {R package version 1.9.12},
    url = {https://CRAN.R-project.org/package=psych},
  }