The original of every document filed and required to be served upon parties to a proceeding shall be endorsed with a certificate of service signed by the party making service or by the party's attorney or representative, stating that such service has been made, the date of service, and the manner of service, whether by mail or personal delivery.

[35 FR 10760, July 2, 1970, as amended at 51 FR 10386, Mar. 26, 1986]