Mich. Comp. Laws § 331.75: Bond or note holders; vested rights, impairment.

Sec. 45.

The state pledges and agrees with the holders of any notes or bonds issued under this act, that the state will not limit or alter the rights vested in any authority to fulfill the terms of any agreements made with the holders thereof, or in any way impair the rights and remedies of the holders until the notes or bonds, together with the interest thereon, with interest on any unpaid installments of interest and all costs and expenses in connection with any action or proceeding by or on behalf of such holders, are fully met and discharged. Any authority is authorized to include this pledge and agreement of the state in any agreement with the holders of such notes or bonds.