Useful Web Resources on Copyright Law and Fair Use:

United States Copyright Office

Excerpt from https://www.copyright.gov/title17/ US Copyright Law contains a list of the various purposes for which the reproduction of a particular work may be considered “fair,” such as criticism, comment, news reporting, teaching, scholarship, and research. US Copyright Law also sets out four factors to be considered in determining whether or not a particular use is fair:

  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. amount and substantial of the portion used in relation to the copyrighted work as a whole; and
  4. the effect of the use upon the potential market for or value of the copyrighted work.

The distinction between “fair use” and infringement may be unclear and not 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.

Links:

The Copyright Laws and Fair Use (The University of Iowa Libraries)
Copyright and Multimedia Law for Web Builders and Multimedia Authors (University of Iowa Libraries)

US Copyright Law (US Copyright Office)

DMCA - Exemption Procedures (University of Iowa)

Copyright and the University of Iowa