To cite package ‘pcdid’ in publications use:

  Chan M, Wang X (2025). _pcdid: Principal Components
  Difference-in-Differences_. R package version 1.0.0.9000,
  <https://github.com/adamwang15/pcdid>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {pcdid: Principal Components Difference-in-Differences},
    author = {Marc Chan and Xiaolei Wang},
    year = {2025},
    note = {R package version 1.0.0.9000},
    url = {https://github.com/adamwang15/pcdid},
  }