To cite package ‘epidatr’ in publications use:

  Farrow DC, Brooks LC, Rumack A, Tibshirani RJ, Rosenfeld R (2015).
  “Delphi Epidata API.” <https://github.com/cmu-delphi/delphi-epidata>.

A BibTeX entry for LaTeX users is

  @Misc{,
    title = {Delphi Epidata API},
    author = {David C. Farrow and Logan C. Brooks and Aaron Rumack and Ryan J. Tibshirani and Roni Rosenfeld},
    year = {2015},
    url = {https://github.com/cmu-delphi/delphi-epidata},
  }