19 CFR 141.31: General requirements and definitions.

(a) Limited or general power of attorney. A power of attorney may be executed for the transaction by an agent or attorney of a specified part or all the Customs business of the principal.

(b) [Reserved]

(c) Minor agents. A power of attorney to a minor shall not be accepted.

(d) Definitions of resident and nonresident. For the purposes of this subpart, “resident” means an individual who resides within, or a partnership one or more of whose partners reside within, the Customs territory of the United States or the Virgin Islands of the United States, or a corporation incorporated in any jurisdiction within the Customs territory of the United States or in the Virgin Islands of the United States. A “nonresident” means an individual, partnership, or corporation not meeting the definition of “resident.”