Gaya APA

Covey, S. (1990). The 7 Habits of Highly Effective People: Restoring the Character Ethic . New York: A Fireside Book/Simon & Schuster.

Gaya MLA

Covey, Stephen. "The 7 Habits of Highly Effective People: Restoring the Character Ethic". New York: A Fireside Book/Simon & Schuster, 1990. Book.