Gaya APA

KOUZES, J, M., POSNER, B, Z. (2007). THE LEADERSHIP CHALLENGE (4th). San Francisco: JOHN WILEY & SON.

Gaya MLA

KOUZES, James, M.., POSNER, Barry, Z.. "THE LEADERSHIP CHALLENGE". 4th San Francisco: JOHN WILEY & SON, 2007. Text.