International IRS Publications:

Pub. 54, Tax Guide for U.S. Citizens and Resident Aliens Abroad

Pub. 80, Circular SS - Federal Tax Guide for Employers in the U.S. Virgin Islands, Guam, American Samoa, and the Commonwealth of the Northern Mariana Islands

Pub. 514, Foreign Tax Credit for Individuals

Pub. 515, Withholding of Tax on Nonresident Aliens and Foreign Entities  

Pub. 516, U.S. Gov’t Civilian Employees Stationed Abroad

Pub. 519, U.S. Tax Guide for Aliens

Pub. 570, Tax Guide for Individuals With Income From U.S. Possessions

Pub. 593, Tax Highlights for U.S. Citizens and Residents Going Abroad

Pub. 597, United States — Canada Income Tax Treaty

Pub. 901, U.S. Tax Treaties

Pub 1187, Specifications for Electronic Filing of Form 1042-S, Foreign Person's U.S. Source Income Subject to Withholding

Pub 1321, Special Instructions For Bona Fide Residents Of Puerto Rico Who Must File A U.S. Individual Income Tax Return

Pub 4588, Basic Tax Guide for Green Card Holders

Pub 4732, Federal Tax Information for U.S. Taxpayers Living Abroad