Although I have not used any formal contracts (you don't really need a document with the word "contract" in the title to have a contract), I wrote a map documentation which I handed to the client in a separate PDF file.
It contains a smaller version of the map as well as any information I am legally required to hand over to the client (such as the reference to textures.com) plus the license info, which tells the client in an understandable language how he may use the map.