N.J. Stat. § 43:15A-111
This act shall become operative with regard to a pension fund, other than the Public Employees' Retirement System, the Teachers' Pension and Annuity Fund, a county pension fund established pursuant to R.S. 43:10-1 et seq. for employees of a county of the first class having a population of less than 800,000 according to the 1980 federal decennial census, or a county pension fund established pursuant to P.L. 1948, c.310 (C.43:10-18.50 et seq.) for employees of a county having a population of from 300,000 to 325,000 inhabitants according to the federal census of 1940, supported in whole or in part by the State or by one or more counties, municipalities, or school districts, 60 days after a majority of the members of such pension fund qualified to vote in a referendum as required by 218(d)(3) of the Social Security Act shall have voted to be covered under the terms of that act, provided that the conditions for holding such referendum as set forth in P.L. 1951, c.253, as amended and supplemented have been met.
N.J.S. § 43:15A-111