The city may issue revenue bonds for any public purpose without first submitting the question of their issuance to the registered electors, and may pledge the revenues therefrom to pay the bonds and interest thereon; provided that if any such bonds pledge the revenue of any other city-owned utility, property or facility, or if the said bonds are in any way made a general obligation of the city, then such bonds shall require the affirmative vote of a majority of the registered electors voting thereon before they may be issued. (Ord. No. 87-202, § 47, 11-3-1987; Ord. No. 91-47, § 1, 11-13-1991)