To cite npi in publications, please use:

  Farach F (2022). _npi: Access the U.S. National Provider Identifier
  Registry API_. doi:10.5281/zenodo.6326729
  <https://doi.org/10.5281/zenodo.6326729>. R package version 0.3.1,
  <https://github.com/ropensci/npi>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{npi}: Access the U.S. National Provider Identifier Registry API},
    author = {Frank Farach},
    url = {https://github.com/ropensci/npi},
    year = {2022},
    doi = {10.5281/zenodo.6326729},
    note = {R package version 0.3.1},
  }