To cite didimputation in publications use:

  Butts, Kyle (2021).  didimputation: Difference-in-Differences
  estimator from Borusyak, Jaravel, and Spiess (2021)R package version
  0.5.0.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {didimputation: Difference-in-Differences estimator from Borusyak, Jaravel, and Spiess (2021)},
    author = {Kyle Butts},
    year = {2021},
    url = {https://github.com/kylebutts/didimputation},
  }