To cite package ‘orcutt’ in publications use:

  Stefano S, Quartagno M, Tamburini M, Robinson D (2018). _orcutt:
  Estimate Procedure in Case of First Order Autocorrelation_.
  <https://CRAN.R-project.org/package=orcutt>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{orcutt}: Estimate Procedure in Case of First Order Autocorrelation},
    author = {Spada Stefano and Matteo Quartagno and Marco Tamburini and David Robinson},
    year = {2018},
    url = {https://CRAN.R-project.org/package=orcutt},
  }