Bankrate
Bankrate: Tax Basics, Choosing the Correct Form
Description of the 3 forms, 1040EZ. 1040A and 1040. Explains who should use each form when filing taxes and why.
Thomson Reuters
Find Law: Annotation 2: Sixteenth Amendment
This resource describes the different types of income that are taxable by the government based on numerous court cases in which definitions of the 16th amendment Corporation Tax Act of 1909 were applied.