Hatzinger, Reinhold, and Regina Dittrich. “Prefmod: An R Package for Modeling Preferences Based on Paired Comparisons, Rankings, or Ratings”. Journal of Statistical Software 48, no. 10 (May 24, 2012): 1–31. Accessed August 9, 2022. https://www.jstatsoft.org/index.php/jss/article/view/v048i10.