To cite package ‘xtvfreg’ in publications use:

  Liao T (2025). _xtvfreg: Variance Function Panel Regression_. R
  package version 1.1.0, <https://CRAN.R-project.org/package=xtvfreg>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {xtvfreg: Variance Function Panel Regression},
    author = {Tim F. Liao},
    year = {2025},
    note = {R package version 1.1.0},
    url = {https://CRAN.R-project.org/package=xtvfreg},
  }