(1) For the dispositions of a spouse set out in section 1511 to 1515 to be effective, the approval of the other spouse is required.
(2) The approval may not be given through an agent. The declaration of approval is to be recorded by a notary. The approval is irrevocable.
(3) The spouses may also make the dispositions set out in sections 1511 to 1515 in a joint will.