N.Y. Comp. Codes R. & Regs. tit. 4, § 201.4 – Showing of interest.

(a) A showing of interest shall be filed simultaneously with a petition or motion to intervene.
(b) In determining whether the evidence submitted to establish a showing of interest is timely, the director shall accept evidence of current membership. The director shall also accept dues deduction authorizations, original designation cards, or petitions on a form prescribed by the board, all of which were signed and dated within one year of their submission. A showing of interest may consist of any combination of the foregoing evidence, membership lists, dues deduction authorizations. Designation cards shall be submitted in alphabetical order. The director may require that an alphabetized listing of the names of the signatories on individually signed and dated petitions be filed within a reasonable period of time after submission of the showing of interest petitions. If such an alphabetized listing is required, the person or persons filing the listing shall simultaneously file with the director a signed attestation that the listing sets forth only the names of the signatories on the showing of interest petitions.
(c) A determination by the director that a showing of interest is timely and that it is numerically sufficient is a ministerial act and cannot be reviewed by the board.
(d) A declaration of authenticity shall be filed by the petitioner or, in the case of a motion to intervene, the movant, with the director simultaneously with the filing of the showing of interest. Such declaration shall contain the following:
1. (1) the name of the individual executing the declaration, and a statement of the declarant's authority to execute it;
2. (2) a declaration that, upon the declarant's personal knowledge or upon the declarant’s inquiries, the persons whose names appear on the evidence submitted have themselves signed such evidence on the dates specified thereon, and that the persons specified as current members are in fact current members and, that inquiry was made regarding their inclusion in the negotiating unit which is the subject of the representation petition. If the declaration is upon inquiries the declarant has made, and not upon the declarant's personal knowledge, the declarant shall specify the nature of those inquiries; and
3. (3) a signed affirmation stating, “I affirm under penalties of perjury under the laws of New York, which may include a fine or imprisonment, that the foregoing is true, and I understand that this document will be filed in a proceeding before the Public Employment Relations Board.”
(e) The director may direct an investigation and, if necessary, a hearing to ascertain whether the evidence submitted is accurate. If it is determined after investigation or hearing that the evidence is fraudulent or that the declaration is false, such reasonable action as is appropriate to protect the integrity of the procedures of the board in connection with the pending matter shall be taken. Such a determination and such action taken shall be reviewable by the board pursuant to Part 213 of this Title.