Mich. Comp. Laws § 38.706: Municipal employees' retirement system; coverage of employees of public libraries.

Sec. 6.

In lieu, however, of formulating any plan under the foregoing sections of this act the library board and the local legislative body may, by concurrent resolution, adopt and put into effect for the employes of the library any plan which may have been, or may hereafter be, adopted for the employes of the city.