This is a good website that is ran by the government that talks all about copyright and the rules and regulations and the process for how to get a copyright. This is very good resource.
I like this website because it describes repetition in detail. I like the examples it has as well. Also, I like on the sidebar how you can go to other principles of design.
CREATIVE COMMONS. This PDF tells, for those who are better absorbing information by reading it rather than seeing a cute video, more about what the creative commons is, who it's being done by, and how it can be applied to our lives.