It is important to discuss citation expectations with your students, and not assume they know how to cite. Instructors should provide information on how to credit academic sources, and refer students to resources for additional support (e.g. liaison librarian, citation style guides, citation management software, etc.).
Ensure all of your teaching materials properly acknowledge all sources (including course notes, charts, data, tables, figures, maps, PowerPoint presentations, etc.) so that you lead by example.