To cite package ‘earth’ in publications use:

  Milborrow S, Hastie T, Tibshirani R (2024). _earth: Multivariate
  Adaptive Regression Splines_. R package version 5.3.4,
  <https://CRAN.R-project.org/package=earth>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {earth: Multivariate Adaptive Regression Splines},
    author = {Stephen Milborrow and Trevor Hastie and Rob Tibshirani},
    year = {2024},
    note = {R package version 5.3.4},
    url = {https://CRAN.R-project.org/package=earth},
  }