I am making a one off tv documentary where I wish to include a short animation. The animation is a totally complete entity in itself with titles etc and is currently distributed as a finished short film. It's five minutes long and I do have permission from the owner to include it. What kind of release forms or licenses should I get signed to cover me in case of any future disputes? Especially as it's a major part of the programme and I don't want it's inclusion jeopardised. Many thanks.