Gaya APA

Covey, S, R. (1990). The 7 Habits Of Highly Effective People : Powerful Lessons in Personal Change . New York: Simon & Schuster New York.

Gaya MLA

Covey, Stephen, R.. "The 7 Habits Of Highly Effective People : Powerful Lessons in Personal Change". New York: Simon & Schuster New York, 1990. Text.