When citing nhdR, please cite both the package and underlying data sources used:

Stachelek J (2019). Tools for working with the National Hydrography Dataset. https://cran.r-project.org/package=nhdR.

USGS (2019). National Hydrography Dataset. Technical Report. United States Geological Survey. https://nhd.usgs.gov/.

Corresponding BibTeX entries:

  @Manual{,
    author = {Joseph Stachelek},
    title = {Tools for working with the National Hydrography Dataset},
    year = {2019},
    url = {https://cran.r-project.org/package=nhdR},
  }

  @Manual{,
    author = {{USGS}},
    title = {National Hydrography Dataset. Technical Report. United
      States Geological Survey},
    year = {2019},
    url = {https://nhd.usgs.gov/},
  }