To cite package 'difNLR' in publications use:

Hladka A, Martinkova P (2019). difNLR: DIF and DDF Detection by Non-Linear Regression Models.. R package version 1.3.0, https://CRAN.R-project.org/package=difNLR.

Drabinova A, Martinkova P (2017). “Detection of Differential Item Functioning with Nonlinear Regression: A Non-IRT Approach Accounting for Guessing.” Journal of Educational Measurement, 54(4), 498-517. doi: 10.1111/jedm.12158.

Corresponding BibTeX entries:

  @Manual{,
    title = {{difNLR}: {DIF} and {DDF} Detection by Non-Linear
      Regression Models.},
    author = {Adela Hladka and Patricia Martinkova},
    year = {2019},
    note = {R package version 1.3.0},
    url = {https://CRAN.R-project.org/package=difNLR},
  }
  @Article{,
    title = {{D}etection of Differential Item Functioning with
      Nonlinear Regression: {A} Non-{IRT} Approach Accounting for
      Guessing},
    author = {Adela Drabinova and Patricia Martinkova},
    year = {2017},
    journal = {Journal of Educational Measurement},
    volume = {54},
    number = {4},
    pages = {498-517},
    doi = {10.1111/jedm.12158},
    publisher = {Wiley Online Library},
  }