Mich. Comp. Laws § 331.61

Sec. 31. (1) The provisions of this act and any resolution and any mortgage or deed of trust shall continue in effect until the principal and interest on the bonds has been fully paid and the duties of the hospital authority and its commission and officers under this act and any resolution and any mortgage or deed of trust shall be enforceable by any bondholder by mandamus, foreclosure of the mortgage or deed of trust or other appropriate action in any court of competent jurisdiction. (2) The resolution authorizing the bonds shall provide that the bonds shall contain a recital that they are issued pursuant to this act, which recital shall be conclusive evidence of their validity and of the regularity of their issuance. (3) Any resolution authorizing the issuance of bonds under this act shall not be effective until publication once in a newspaper of general circulation within the incorporating unit.