45 CFR 501.6: Documentary evidence.

Documentary evidence may consist of books, records, correspondence or other documents pertinent to any hearing, examination, or investigation within the jurisdiction of the Commission. The application for the issuance of subpoenas for production of documents must specify the books, records, correspondence or other documents sought. The production of documentary evidence will not be required at any place other than the witness's place of business. The production of such documents will not be required at any place if, prior to the return date specified in the subpoena, the person either has furnished the issuer of the subpoena with a properly certified copy of the documents or has entered into a stipulation as to the information contained in the documents.