To cite package ‘splmm’ in publications use:

  Yang L, Sun E, Wu T (2024). _splmm: Simultaneous Penalized Linear
  Mixed Effects Models_. R package version 1.2.0,
  <https://CRAN.R-project.org/package=splmm>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {splmm: Simultaneous Penalized Linear Mixed Effects Models},
    author = {Luoying Yang and Eli Sun and Tong Tong Wu},
    year = {2024},
    note = {R package version 1.2.0},
    url = {https://CRAN.R-project.org/package=splmm},
  }