[Inkscape-user] Logo and banner usage

Hi,

I use inkscape create some creative works. Is it allowed to put some banner like "powered by inkscape" on them? ( like the logo, http://inkscape.org/images/inkscape_button.svg ) After some search, I haven't found pages that clear say how I can use logo, and where the official location it is. Would anyone like to answer me here or give me some hint to get the answer?

sincerely, Mat.