Many universities point faculty members to Circular 21 published by the United States Copyright Office.
"The bill endorses the purpose and general scope of the judicial doctrine of fair use, but there is no disposition to freeze the doctrine in the statute, especially during a period of rapid technological change. Beyond a very broad statutory explanation of what fair use is and some of the criteria applicable to it, the courts must be free to adapt the doctrine to particular situations on a case-by-case basis. Section 107 is intended to restate the present judicial doctrine of fair use, not to change, narrow, or enlarge it in any way."
Circular 21 makes it very clear that nothing in the Copyright Act is meant to create a rigid test for the application of the fair use doctrine.