No person may be required to appear at a hearing or to testify at a hearing unless there has been personally served upon him prior to the time when he is required to appear, a copy of this act, and a general statement of the subject of the investigation. A copy of the resolution, statute, order or other provision of law authorizing the investigation shall be furnished by the agency upon request therefor by the person summoned.
N.J.S. § 52:13E-2