If you are unsure if your use of copyrighted material meets criteria laid out in the four-factor analysis, you can always ask for permission from a copyright holder to use their work.
To the left is a model permissions letter from Duke University Libraries. Click on the letter to download a Word Document version that you can explore, modify, and use yourself. Keep in mind that this is only a sample letter and specific situations will require slightly different language or documents.
Ask a librarian if you need assistance!