Sec. 18. (a) A document of gift is valid if executed in accordance with:
(1) this chapter;
(2) the laws of the state or country where it was executed; or
(3) the laws of the state or country where the person making the anatomical gift was domiciled, has a place of residence, or was a national at the time the document of gift was executed.
(b) If a document of gift is valid under this chapter, the law of this state governs the interpretation of the document of gift.
(c) A person may presume that a document of gift or amendment of an anatomical gift is valid unless that person knows that it was not validly executed or was revoked.