To cite package ‘psme’ in publications use:

  Li Z (2025). _psme: Penalized Splines Mixed-Effects Models_. R
  package version 1.0.0, <https://github.com/zheyuanli/psme>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {psme: Penalized Splines Mixed-Effects Models},
    author = {Zheyuan Li},
    year = {2025},
    note = {R package version 1.0.0},
    url = {https://github.com/zheyuanli/psme},
  }