To cite package ‘sjPlot’ in publications use:

  Lüdecke D (????). _sjPlot: Data Visualization for Statistics in
  Social Science_. R package version 2.8.16.2,
  <https://CRAN.R-project.org/package=sjPlot>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {sjPlot: Data Visualization for Statistics in Social Science},
    author = {Daniel Lüdecke},
    note = {R package version 2.8.16.2},
    url = {https://CRAN.R-project.org/package=sjPlot},
  }