Proper way of citing Octave in scientific papers

[Rafael Laboissiere]

I came across the following paper:

    P Filzmoser, R Maronnab, and M Werner (2008) Computational Statistics &
      Data Analysis, 52:1694-1711
  
that contains the following sentence:

    "All programs were executed in R (R Development Core Team, 2005) except
    for Kurtosis1, which was carried out in the Octave programming
    environment (http://www.octave.org), a free version mostly compatible
    with Matlab."

The entry for "R Development Core Team, 2005" at the end of the paper
corresponds to the output of the command below (in R):
    
########################################################################    
> citation()

To cite R in publications use:

  R Development Core Team (2008). R: A language and environment for
  statistical computing. R Foundation for Statistical Computing,
  Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {R: A Language and Environment for Statistical Computing},
    author = {{R Development Core Team}},
    organization = {R Foundation for Statistical Computing},
    address = {Vienna, Austria},
    year = {2008},
    note = {{ISBN} 3-900051-07-0},
    url = {http://www.R-project.org},
  }

We have invested a lot of time and effort in creating R, please cite it
when using it for data analysis. See also ‘citation("pkgname")’ for
citing R packages.
########################################################################

Curiously enough the ISBN above (3-900051-07-0) does not correspond to any 
real book but to the reference manual of R that is automatically generated
when building from the sources.

My question is: what is the appropriate way of citing Octave in scientific
papaers?  Just use the GNU Octave Manual JW  Eaton, D Bateman, and S
Hauberg?  What about adding a citation() command to Octave?

-- 
Rafael Laboissière