Covey, S. R. (2020). 7 Habits of Highly Effective People. Simon and Schuster.
Chicago-viite (17. p.)Covey, Stephen R. 7 Habits of Highly Effective People. New Delhi: Simon and Schuster, 2020.
MLA-viite (9. p.)Covey, Stephen R. 7 Habits of Highly Effective People. Simon and Schuster, 2020.
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