To cite package ‘qif’ in publications use:

Jiang Z, Song P (2019). qif: Quadratic Inference Function. R package version 1.5, https://github.com/umich-biostatistics/qif.

Corresponding BibTeX entry:

  @Manual{,
    title = {qif: Quadratic Inference Function},
    author = {Zhichang Jiang and Peter Song},
    year = {2019},
    note = {R package version 1.5},
    url = {https://github.com/umich-biostatistics/qif},
  }