APA

Covey S. R., . (1990). The Seven Habits of Highly Effetive People. New York: A Fireside Book.

Chicago

Covey Stephen R, . 1990. The Seven Habits of Highly Effetive People. New York: A Fireside Book.

Harvard

Covey S. R., . (1990). The Seven Habits of Highly Effetive People. New York: A Fireside Book.

MLA

Covey Stephen R, . The Seven Habits of Highly Effetive People. New York: A Fireside Book. 1990.