To cite package ‘ctrialsgov’ in publications use:

  Arnold T, Wei A, Kane M (2021). _ctrialsgov: Query Data from U.S.
  National Library of Medicine's Clinical Trials Database_. R package
  version 0.2.5, <https://CRAN.R-project.org/package=ctrialsgov>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ctrialsgov: Query Data from U.S. National Library of Medicine's Clinical
Trials Database},
    author = {Taylor Arnold and Auston Wei and Michael J. Kane},
    year = {2021},
    note = {R package version 0.2.5},
    url = {https://CRAN.R-project.org/package=ctrialsgov},
  }