26 C.F.R. § 521.102 Applicable provisions of the Internal Revenue Code.
Title 26 - Internal Revenue
(a) The Internal Revenue Code provides in part as follows:
Chapter I—Income Tax * * * * * * * * * * (b) Exclusions from gross income. The following items shall not be included in gross income and shall be exempt from taxation under this chapter: * * * * * (7) Income exempt under treaty. Income of any kind, to the extent required by any treaty obligation of the United States; * * * * * (b) Pursuant to section 62 of the Internal Revenue Code, other provisions of the internal revenue laws, and to Article XXII of the convention, the following regulations, which are designated as §§521.101 to 521.117 are hereby prescribed and all regulations inconsistent herewith are modified accordingly.
Title 26: Internal Revenue
PART 521—DENMARK
Subpart—General Income Tax
Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish Corporations
§ 521.102 Applicable provisions of the Internal Revenue Code.

