Citation of gnuplot in a scientific publication

[Peter J. <pet...@gm...>]

Dear gnuplot-beta list,

I want to cite gnuplot in my publication. Is the following reference OK?

Williams, T. and Kelley, C. (2011). Gnuplot 4.5: an interactive
plotting program. URL http://gnuplot.info. (Last accessed: 2011 June
7)

(I've found one instance of this question in the list archives, that's
where the above comes from.)

Péter Juhász