To cite package ‘ei’ in publications use:

King G, Roberts M, Kenny C, Eshima S (2026). ei: Ecological Inference. R package version 2.0.0, https://github.com/iqss-research/ei.

Corresponding BibTeX entry:

  @Manual{,
    title = {ei: Ecological Inference},
    author = {Gary King and Molly Roberts and Christopher T. Kenny and
      Shusei Eshima},
    year = {2026},
    note = {R package version 2.0.0},
    url = {https://github.com/iqss-research/ei},
  }