The authorization in sections 7-339a to 7-339l, inclusive, to receive, obtain, provide or furnish any services, facilities, personnel, equipment, property or other resources, or perform or engage in any functions or activities by means of an interlocal agreement, shall be in addition to and not in substitution for or in limitation of any authorizations for joint or cooperative agreements or undertakings contained in other provisions of the law of this state; provided, if any of the provisions of said sections are in conflict with any other statutes of this state providing for the authorization or performance of joint or cooperative agreements or undertakings between public agencies of this state and public agencies of other states, the provisions of such other statutes shall be controlling.