To cite GNU Octave in publications use:

  John W. Eaton, David Bateman, Søren Hauberg, Rik Wehbring (2020).
  GNU Octave version 6.1.0 manual: a high-level interactive language for
  numerical computations.
  URL https://www.gnu.org/software/octave/doc/v6.3.0/

A BibTeX entry for LaTeX users is:

  @manual{,
    title     = {{GNU Octave} version 6.3.0 manual: a high-level interactive language for numerical computations},
    author    = {John W. Eaton and David Bateman and S{\o}ren Hauberg and Rik Wehbring},
    year      = {2021},
    url       = {https://www.gnu.org/software/octave/doc/v6.3.0/},
  }

We have invested a lot of time and effort in creating GNU Octave, please
cite it when using it.  See also 'citation pkgname' for citing Octave
packages.