https://open.lib.umn.edu/organizationalbehavior/chapter/12-2-who-is-a-leader-trait-approaches-to-leadership/
https://open.lib.umn.edu/organizationalbehavior/chapter/12-3-what-do-leaders-do-behavioral-approaches-to-leadership/
https://open.lib.umn.edu/organizationalbehavior/chapter/12-4-what-is-the-role-of-the-context-contingency-approaches-to-leadership/
https://open.lib.umn.edu/organizationalbehavior/chapter/12-5-whats-new-contemporary-approaches-to-leadership/