Mich. Comp. Laws § 331.302

Sec. 2. The common council of any city availing itself of the provisions of this act, shall have the power to fix the time and place of payment of the principal and interest voted under the provisions of this act, and to issue the bonds or other evidences of indebtedness of such city: Provided, That it shall not be lawful for the common council of any such city to borrow any portion of said sum of money unless the question of borrowing the same shall have been first submitted to the electors of such city at its annual election, or at a special election called for that purpose by the common council of such city, and shall have been adopted by a 3/5 vote of the electors voting at such election.