The Internal Revenue Code (IRC) is the supreme source of income tax law. When trying to resolve an income tax question, a tax practitioner will look to other sources in addition to the IRC. For example, the tax practitioner may consult IRC regulations, revenue rulings, procedures, private letter rulings, and court cases. What are some reasons a tax practitioner would not consult only the IRC? Why is there a need for administrative rulings and court cases? If court cases conflict in their rulings, which ruling should you rely on and why?