Section 31-C - Participation by the Metropolitan Reference and Research Library Agencya. The Metropolitan Reference and Research Library Agency may, by resolution adopted by its board of trustees and approved by the comptroller, elect to participate in the retirement system. Acceptance of its employees for membership in the retirement system shall be optional with the comptroller, who shall determine the amounts of contribution payable by such agency and its employees, shall resolve questions of credit for prior service, and shall in all other respects assure that such employees share the same rights, obligations and benefits as other members of the retirement system.b. The officers and employees of such agency shall be credited with such periods of prior service as shall be certified by such agency for service rendered to it, or the state, or in any other capacity approved by such agency and the comptroller. Service for such agency after the date on which it commences to participate in the retirement system shall be considered as member service. An officer or employee of such agency who, as of the date he or she is so approved for membership in the retirement system, is already a member thereof, shall not have his or her total credit reduced by such approval. Any reserve held on account of any such officer or employee in the pension accumulation fund shall be used as an offset against the deficiency contribution payable thereafter by such agency on account of such officer or employee for any prior service credit and any such previous credit.N.Y. Retire. and Soc. Sec. Law § 31-C