To cite package ‘DCPO’ in publications use:

  Solt F (2020). _DCPO: Dynamic Comparative Public Opinion_. R package
  version 0.5.3, <https://CRAN.R-project.org/package=DCPO>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {DCPO: Dynamic Comparative Public Opinion},
    author = {Frederick Solt},
    year = {2020},
    note = {R package version 0.5.3},
    url = {https://CRAN.R-project.org/package=DCPO},
  }