Although the U.S. Copyright Office has not approved the copying parameters you will find posted on the Internet by many academic institutions, we have included them with the expectation that your carefully review and apply ethically the Fair Use guidelines.
What is fair use?
Fair use is an exception to the exclusive protection of copyright under American law. It permits certain limited uses without permission from the author or owner. Depending on the circumstances, copying may be considered "fair" for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship or research.
To determine whether a specific use under one of these categories is "fair," courts are required to consider the following factors:
1. The purpose and character of the use, including whether such use is of commercial nature or is for nonprofit educational purposes
2. The nature of the copyrighted work
3. The amount and substantiality of the portion used in relation to the copyrighted work as a whole
4. The effect of the use upon the potential market for, or value of, the copyrighted work
The distinction between what is fair use and what is infringement in a particular case will not always be clear or easily defined. There is no specific number of words, lines, or notes that may safely be taken without permission. Acknowledging the source of the copyrighted material does not substitute for obtaining permission.
Copyright protects the particular way authors have expressed themselves. It does not extend to any ideas, systems, or factual information conveyed in a work.
The safest course is to get permission from the copyright owner before using copyrighted material. The Copyright Office cannot give this permission.
Keep in mind that even in an educational setting; it is not fair use to copy for a "commercial motive" or to copy "systematically," that is, "where the aim is to substitute for subscription or purchase." No factor by itself will determine whether a particular use is "fair." All four factors must be weighed together in light of the circumstances. See the U.S. Copyright Office's Copyright Information Circulars and Form Letters for "Circular 21-Reproductions of Copyrighted Works by Educators and Librarians."
If there is any doubt, it is advisable to consult an attorney.