To cite GNU Octave in publications use:

  John W. Eaton, David Bateman, Søren Hauberg, Rik Wehbring (2014).
  GNU Octave version 3.8.1 manual: a high-level interactive language for
  numerical computations.
  CreateSpace Independent Publishing Platform.  ISBN 1441413006,
  URL http://www.gnu.org/software/octave/doc/interpreter/

A BibTeX entry for LaTeX users is:

  @book{,
    author    = {John W. Eaton, David Bateman, S\oren Hauberg, and Rik Wehbring},
    title     = {{GNU Octave} version 3.8.1 manual: a high-level interactive language for numerical computations},
    publisher = {CreateSpace Independent Publishing Platform},
    year      = {2014},
    note      = {{ISBN} 1441413006},
    url       = {http://www.gnu.org/software/octave/doc/interpreter},
  }

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.