To cite the function of the kidney.epi package in publications use:

Bikbov B. (2018) R open source programming code for calculation of the Kidney Donor Profile Index and Kidney Donor Risk Index Kidney Disease. **:***--***

Corresponding BibTeX entry:

  @Article{,
    author = {Boris Bikbov},
    title = {R open source programming code for calculation of the
      Kidney Donor Profile Index and Kidney Donor Risk Index},
    journal = {Kidney Disease},
    year = {2018},
    volume = {*},
    pages = {**--**},
    url = {https://www.karger.com/Journal/Home/261893},
  }