To cite package ‘npreg’ in publications use:

Helwig NE (2026). npreg: Nonparametric Regression via Smoothing Splines. R package version 1.1.1, https://CRAN.R-project.org/package=npreg.

Corresponding BibTeX entry:

  @Manual{,
    title = {npreg: Nonparametric Regression via Smoothing Splines},
    author = {Nathaniel E. Helwig},
    year = {2026},
    note = {R package version 1.1.1},
    url = {https://CRAN.R-project.org/package=npreg},
  }