The United States Supreme Court held that a nontaxpayer has standing to bring a tax refund action under the Internal Revenue Code and that the term "taxpayer" in the Internal Revenue Code is not limited to the party assessed a tax.
United States v. Williams, 115 S. Ct. 1611 (1995).
Paul H. Minton,
Taxation - Internal Revenue Code - Waiver of Sovereign Immunity,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol34/iss2/12