Ref Code Section 871 (b) and 882:
According to these code sections if a foreign person is engaged in a U.S trade or business, he is subject to U.S taxes for any income that is connected...
Foreign Corporations and non-resident aliens who have a U.S source income are subject to U.S Taxation.
According to codes section 871 (b) and 882, all Foreign Persons are taxed at...