27 C.F.R. § 70.111
(b) Person defined. For purposes of Subchapter B of Chapter 68 of the Internal Revenue Code, the term “person” includes an officer or employee of a corporation, or a member or employee of a partnership, who as such officer, employee, or member is under a duty to perform the act in respect of which the violation occurs.
(26 U.S.C. 6671)
[T.D. ATF-251, 52 FR 19314, May 22, 1987. Redesignated by T.D. ATF-301, 55 FR 47606, Nov. 14, 1990]