To cite package ‘classInt’ in publications use:

  Bivand R (2023). _classInt: Choose Univariate Class Intervals_. R
  package version 0.4-10, , <https://github.com/r-spatial/classint>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {classInt: Choose Univariate Class Intervals},
    author = {Roger Bivand},
    year = {2023},
    note = {R package version 0.4-10, 
},
    url = {https://github.com/r-spatial/classint},
  }