> under Urheberrecht an author can always revoke the rights of the publisher Yes and no. There is such a thing as an irrevocable usage right. But I'll concede

> under Urheberrecht an author can always revoke the rights of the publisher Yes and no. There is such a thing as an irrevocable usage right. But I'll concede that even an irrevocable right can be nullified under the right conditions (e.g. if the person granting it wasn't actually in the legal position to do so).