Michigan Compiled Laws, Chapter 442. Sales § 442.324

Sec. 4. (1) The rights and liabilities created by this act are in addition to and not in substitution, exclusion, or displacement of other rights and liabilities provided by law, including the law of principal and agent, except where the construction would, as a matter of law, be unreasonable.

(2) An art merchant who, as buyer, is excluded from obtaining the benefits of an express warranty under this act shall not be deprived of the benefits of any other provision of law.

(3) An art merchant whose warranty of authenticity of authorship was made in good faith shall not be liable for damages beyond the return of the purchase price which the art merchant received.

(4) This act shall not apply, and the art multiples sales act shall apply, to a right, liability, or obligation prescribed by the art multiples sales act,  1 except as provided by that act.