To cite package ‘sstvars’ in publications use:

  Virolainen S (2024). _sstvars: Toolkit for Reduced Form and
  Structural Smooth Transition Vector Autoregressive Models_. R package
  version 1.0.1, <https://CRAN.R-project.org/package=sstvars>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {sstvars: Toolkit for Reduced Form and Structural Smooth Transition Vector
Autoregressive Models},
    author = {Savi Virolainen},
    year = {2024},
    note = {R package version 1.0.1},
    url = {https://CRAN.R-project.org/package=sstvars},
  }