The secretary shall keep a record of the proceedings of the authority and shall be custodian of all books, documents, and papers filed with the authority and of its minute book and seal. He shall have the authority to cause to be made copies of all minutes and other records and documents of the authority and to give certificates, under the seal of the authority, to the effect that such copies are true copies, and all persons dealing with the authority may rely upon such certificates. Resolutions of the authority need not be published or posted unless the authority shall so direct.