To cite package ‘qfa’ in publications use:

  Li T (2026). _qfa: Quantile-Frequency Analysis (QFA) of Time Series
  and Spline Quantile Regression (SQR)_. R package version 5.0,
  <https://CRAN.R-project.org/package=qfa>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {qfa: Quantile-Frequency Analysis (QFA) of Time Series and Spline
Quantile Regression (SQR)},
    author = {Ta-Hsin Li},
    year = {2026},
    note = {R package version 5.0},
    url = {https://CRAN.R-project.org/package=qfa},
  }
