To cite DFIT in publications use:

Victor H. Cervantes (2017). DFIT: An R Package for Raju's Differential Functioning of Items and Tests Framework. Journal of Statistical Software, 76(5), 1-24.<doi:10.18637/jss.v076.i05>

Corresponding BibTeX entry:

  @Article{,
    title = {{DFIT}: An {R} Package for Raju's Differential Functioning
      of Items and Tests Framework},
    author = {V\'ictor H. Cervantes},
    journal = {Journal of Statistical Software},
    year = {2017},
    volume = {76},
    number = {5},
    pages = {1--24},
    doi = {10.18637/jss.v076.i05},
  }