To cite package ‘apca’ in publications use:

  Mulyanto A, Otok B, Purnomo J (2026). _apca: Advanced Principal
  Component Analysis_. R package version 1.0.0,
  <https://CRAN.R-project.org/package=apca>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {apca: Advanced Principal Component Analysis},
    author = {Angga Dwi Mulyanto and Bambang Widjanarko Otok and Jerry Dwi Trijoyo Purnomo},
    year = {2026},
    note = {R package version 1.0.0},
    url = {https://CRAN.R-project.org/package=apca},
  }