Русско-англо-русский юридический словарь

licensing agreement – written contract under which the owner of a copyright, know how, patent, servicemark, trademark, or other intellectual property, allows a licensee to use, make, or sell copies of the original. Such agreements usually limit the scope or field of the licensee, and specify whether the license is exclusive or non-exclusive, and whether the licensee will pay royalties or some other consideration in exchange. (BusinessDictionary)

A written contract as the name suggests, is a contract whose terms have been reduced to writing. Written contracts are also commonly signed. However, a written contract may consist of an exchange of correspondence, a letter written by the promisee and assented to by the promisor without signature, or even a memorandum or printed document not signed by either party. (definitions.uslegal.com)

That is not to say that a written contract will always be clearer than a verbal contract. A poorly drafted contract can often present as many difficulties in relation to ambiguity and certainty as a verbal contract can. (The Independent)

An oral contract is a contract, the terms of which have been agreed by spoken communication. This is in contrast to a written contract, where the contract is a written document. There may be written, or other physical evidence, of an oral contract – for example where the parties write down what they have agreed – but the contract itself is not a written one. (Wikipedia)