I would like to sell (for a low price) my new application without DRM (like does Machinarium) on the Ubuntu software center and on a website with Paypal. When I have registered my application the Ubuntu software center and I've selected the licence, I just found "Proprietary" but in my application I have to provide a licence text that something different than just "Proprietary", isn't it? Do you know where I can find this kind of licence text ?