To cite splines2 in publications use:

Wang W, Yan J (2022). splines2: Regression Spline Functions and Classes. R package version 0.4.6, https://CRAN.R-project.org/package=splines2.

Wang W, Yan J (2021). “Shape-Restricted Regression Splines with R Package splines2.” Journal of Data Science, 19(3), 498–517. doi:10.6339/21-JDS1020.

Corresponding BibTeX entries:

  @Manual{splines2-package,
    title = {{splines2}: {R}egression Spline Functions and Classes},
    author = {Wenjie Wang and Jun Yan},
    year = {2022},
    url = {https://CRAN.R-project.org/package=splines2},
    note = {{R} package version 0.4.6},
  }

  @Article{splines2-paper,
    title = {Shape-Restricted Regression Splines with {R} Package
      {splines2}},
    author = {Wenjie Wang and Jun Yan},
    journal = {Journal of Data Science},
    year = {2021},
    volume = {19},
    number = {3},
    pages = {498--517},
    doi = {10.6339/21-JDS1020},
  }