Library material can be in used in your course content. You should follow these best practices when adding resources for students to use.
Material found online such as YouTube videos, documentaries, or other digital content should follow certain procedures for providing access.
Open educational resources (OER) are teaching, learning, and research materials in any medium that reside in the public domain or that have been released under an open license that permits no-cost access, use, adaptation, and redistribution by others.
"7 Things You Should Know About Open Education: Content" via EDUCAUSE. Last modified June 14, 2018.