To cite package ‘smoots’ in publications use:

  Feng Y, Letmathe S, Schulz D (2023). _smoots: Nonparametric
  Estimation of the Trend and Its Derivatives in TS_. R package version
  1.1.4, <https://CRAN.R-project.org/package=smoots>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {smoots: Nonparametric Estimation of the Trend and Its Derivatives in TS},
    author = {Yuanhua Feng and Sebastian Letmathe and Dominik Schulz},
    year = {2023},
    note = {R package version 1.1.4},
    url = {https://CRAN.R-project.org/package=smoots},
  }