To cite the 'BIFIEsurvey' package in publications use:

BIFIE (2019). BIFIEsurvey: Tools for survey statistics in educational assessment. R package version 3.1-33. https://CRAN.R-project.org/package=BIFIEsurvey

Corresponding BibTeX entry:

  @Manual{,
    title = {BIFIEsurvey: Tools for survey statistics in educational
      assessment},
    author = {{BIFIE} and Alexander Robitzsch and Konrad Oberwimmer},
    year = {2019},
    note = {R package version 3.1-33},
    url = {https://CRAN.R-project.org/package=BIFIEsurvey},
  }