 If a written document is lacking the agreement will have no legal bearing since void; it will be unenforceable by law.Pursuant to § 31a I 1 UrhG the author has the right of rescission, § 31a I 3 UrhG.In spite of a valid claim to reasonable compensation, the right of rescission enables the author to change a decision and cancel the granting of rights concerning the use of yet unknown types of use on the whole or just partially without adverse legal consequences.