Every document which is required by this Act or by any rule made thereunder to be signed by the Chairperson of the Authority or by any person subordinate to him or by any officer authorised by him under sub-section (1) of section 42 shall be deemed to be properly signed, if it bears a facsimile of the signature of such Chairperson of the Authority, person or officer printed, engraved, lithographed or impressed by any other mechanical process approved by the Central Government.