Provided that, where such recording has an exceptional documentary character, one copy of it may be preserved in the official archives, without prejudice to the application of the provisions of section 9. Ownership of copyright 11. In determining the person vested with the copyright under this Part, the following principles shall apply: (a) if one person was the author of the work, the rights vest in that person; (b) if two or more persons were the authors of the work of joint ownership, the rights vest in them jointly; and (c) if there is no evidence to the contrary, the author of a work is the individual whose name is indicated on the work as its author. Employed authors 12. Subject to any written law relating to contracts of employment and to the terms of any specific contract of service or for services, when a work is created by an author: (a) in the course of his employment for the Government, a body corporate or another individual; or (b) under a contract for services with, or as a work commissioned by, the Government, a body corporate or another individual, then, in respect of that work, the author's rights, under section 8, shall vest in the Government, body corporate or other person who employed the author or commissioned the work. Duration of copyright 13. (1) Unless otherwise expressly provided in this Act, the rights referred to in sections 8 and 9 shall be protected (a) during the life of the author and for fifty years after his death; or (b) in the case of a work of joint authorship, during the life of the last surviving author and for fifty years after his death; or 17