Several libraries have also created excellent guides to understanding and applying the four factors:
Library Rights under the US Copyright Act Since the inception of copyright law in the US, libraries have enjoyed special rights to promote the progress of science and the useful arts. This page is meant to support libraries in proactively asserting these rights, particularly when signing contracts for digital works under copyright. Below is an illustration of the rights that libraries rely on to fulfill their core missions. In addition to the fair use right codified in Section 107 and the first sale doctrine in Section 109, the US Congress has adopted specific statutory rights affirming the lawfulness of certain activities, particularly those related to accessibility, teaching, learning, and research.