43 CFR § 1812.1-2
Inquiries
June 11, 2020
No person other than officers or employees of the Department of the Interior shall direct any inquiry to any employee of the Bureau with respect to any matter pending before it other than to the head of the unit in which the matter is pending, to a superior officer, or to an employee of the unit authorized by the unit head to answer inquiries.
[35 FR 9513, June 13, 1970]