To cite ic.infer in publications use:

Grömping U (2010). “Inference with Linear Equality and Inequality Constraints Using R: The Package ic.infer.” Journal of Statistical Software, 33(10), 1–31. https://www.jstatsoft.org/v33/i10/.

Corresponding BibTeX entry:

  @Article{,
    title = {Inference with Linear Equality and Inequality Constraints
      Using {R}: The Package {ic.infer}},
    author = {Ulrike Gr{\"o}mping},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {33},
    number = {10},
    pages = {1--31},
    url = {https://www.jstatsoft.org/v33/i10/},
  }