Lutzer, E. W. (1979). How to say no to stubborn habit. Victor Books.
Cita Chicago (17th ed.)Lutzer, Erwin W. How to Say No to Stubborn Habit. Victor Books, 1979.
Cita MLA (9th ed.)Lutzer, Erwin W. How to Say No to Stubborn Habit. Victor Books, 1979.
Atenció: Aquestes cites poden no estar 100% correctes.