Gaya APA

Posner, J, K, B. (2012). The leadership challenge: how to make extraordinary things happen in organizations (ed. 5). San Francisco: Jossey-Bass Publisher.

Gaya MLA

Posner, James, Kouzes;, Barry. "The leadership challenge: how to make extraordinary things happen in organizations". ed. 5 San Francisco: Jossey-Bass Publisher, 2012. Text.