To cite hydrotoolbox in publications use:

Toum E (2021). hydrotoolbox: Hydrological Tools for Handling Hydro-Meteorological Data Records. 1.0.0, https://CRAN.R-project.org/package=hydrotoolbox.

Corresponding BibTeX entry:

  @Manual{,
    title = {hydrotoolbox: Hydrological Tools for Handling
      Hydro-Meteorological Data Records},
    author = {Ezequiel Toum},
    year = {2021},
    note = {1.0.0},
    url = {https://CRAN.R-project.org/package=hydrotoolbox},
  }