26 USC §7655

(a) Imposition of tax in possessions For provisions imposing tax in possessions, see— (1) Chapter 2, relating to self-employment tax; (2) Chapter 21, relating to the tax under the Federal Insurance Contributions Act. (b) Other provisions For other provisions relating to possessions of the United States, see— (1) Section 931, relating to income tax on residents of Guam, American Samoa, or the Northern Mariana Islands; (2) Section 933, relating to income tax on residents of Puerto Rico.