In order to use someone else's copyrighted material, you must have the permission of the owner(s).
In order to use someone else's work, you must have permission from the owner of the copyright. It is often the creator of the work, but it can also be someone else, such as a publisher who acquired the financial copyright when you publish an article.
Copyright also means that you must name both the creator and the potential holder of the economic rights, such as a publisher, when you use the work.
Learn more about
Use of copyrighted material in teaching.
Use of teaching materials created at the University.