To cite the psychTools package in publications use:

Revelle, W. (2019) psychTools:Tools to Accompany the 'psych' Package for Psychological Research Northwestern University, Evanston, Illinois, USA, https://CRAN.R-project.org/package=psychTools Version = 1.9.5.

Corresponding BibTeX entry:

  @Manual{,
    title = {psychTools:Tools to Accompany the 'psych; Package for
      Psychological Research },
    author = {William Revelle},
    organization = { Northwestern University},
    address = { Evanston, Illinois},
    year = {2019},
    note = {R package version 1.9.5},
    url = {https://CRAN.R-project.org/package=psychTools},
  }