N.J. Stat. § 40:63-82: Proceedings after joint contract to be by resolution

Whenever a joint contract shall be made and entered into in writing and duly executed by two or more municipalities under the provisions of this article, all acts and proceedings which may be necessary to be thereafter taken by such municipalities, collectively in joint meeting, or singly in their corporate capacity, relating to the public improvements or works, may be taken by resolution and not by ordinance.