Sec. 7603.
Service of summons
(a) In general - A summons issued under section 6420(e)(2), 6421 (g)(2), 6427(j)(2), or 7602 shall be served by the Secretary, by an attested copy delivered in hand to the person to whom it is directed, or left at his last and usual place of abode; and the certificate of service signed by the person serving the summons shall be evidence of the facts it states on the hearing of an application for the enforcement of the summons. When the summons requires the production of
books, papers, records, or other data, it shall be sufficient if such books, papers, records, or other data are described with reasonable certainty
