Thomson Reuters Checkpoint 
provides primary tax documents and secondary analysis for federal, state, and local taxation, estate planning, pensions and benefits, international taxation, and payroll taxation. It covers tax, auditing, and corporate governance sources.
It can be used to find the following types of information:
1. IRS tax code.
2. IRS and Treasury Department regulations.
3. Legislation and legislative history.
4. Tax court cases.
5. State & local tax rulings
6. Employment laws, rules, & regulations
7. Revenue rulings and letter rulings.
8. To find updates and new developments.
9. To look up other IRS publications.
10. Calculators (mortgage, auto, credit card, retirement, etc.)
The four fastest ways to search Checkpoint are the following:
Use the My Quick Links list.
Use the pulldown menu next to Current View.
Type a keyword into the Navigator Search box on the right side of the screen.
Use the pulldown menu under Search.
Once you have pulled up your document, Checkpoint provides options for printing, exporting, and emailing.