To cite package ‘a4’ in publications use:

  Talloen W, Verbeke T (2026). _a4: Automated Affymetrix Array Analysis
  Umbrella Package_. R package version 1.60.0,
  <https://bioconductor.org/packages/a4>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {a4: Automated Affymetrix Array Analysis Umbrella Package},
    author = {Willem Talloen and Tobias Verbeke},
    year = {2026},
    note = {R package version 1.60.0},
    url = {https://bioconductor.org/packages/a4},
  }