Possible Duplicate:
beamer: footnote text collides with navigation symbols
I know beamer discourages the usage of footnotes. But I think for academic presentations, we always need to mark the resource of figures, or theories. Thus citation (or some simple explanation) is really in need. I plan to incorporate it into the lower navigation bar, where normally are the presentation title or name of presenter (I think it is not necessary, except the audience comes in the middle of your presentation).
