1. a. (1) Any two or more municipalities may unite in the support, maintenance and control of a joint free public library for the use and benefit of the residents of such municipalities.
(2) Every library established under this chapter shall be considered a free public library as defined under R. S. 40:54-1 et seq. and shall have the same benefits, powers, duties and responsibilities granted to free public libraries and their governing boards of trustees.
b. The combined minimum appropriation for the joint free public library annually shall be not less than one-third of a mill on every dollar of assessable property within the participating municipalities based upon the equalized valuation of such property within the combined municipalities as certified by the Director of the Division of Taxation in the Department of the Treasury in accordance with the provisions of R.S.54:4-49.